[libcxx-commits] [compiler-rt] [libunwind] [clang] [llvm] [lld] [libc] [flang] [lldb] [clang-tools-extra] [libcxx] [X86] Use RORX over SHR imm (PR #77964)
Bryce Wilson via libcxx-commits
libcxx-commits at lists.llvm.org
Thu Jan 25 12:23:41 PST 2024
https://github.com/Bryce-MW updated https://github.com/llvm/llvm-project/pull/77964
>From d4c312b9dbf447d0a53dda0e6cdc482bd908430b Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Fri, 12 Jan 2024 16:01:32 -0600
Subject: [PATCH 01/15] [X86] Use RORX over SHR imm
---
llvm/lib/Target/X86/X86InstrShiftRotate.td | 78 ++++++++++++++
llvm/test/CodeGen/X86/atomic-unordered.ll | 3 +-
llvm/test/CodeGen/X86/bmi2.ll | 6 +-
llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll | 3 +-
llvm/test/CodeGen/X86/pr35636.ll | 4 +-
llvm/test/CodeGen/X86/vector-trunc-ssat.ll | 116 ++++++++++-----------
6 files changed, 143 insertions(+), 67 deletions(-)
diff --git a/llvm/lib/Target/X86/X86InstrShiftRotate.td b/llvm/lib/Target/X86/X86InstrShiftRotate.td
index f951894db1890cd..238e8e9b6e97f30 100644
--- a/llvm/lib/Target/X86/X86InstrShiftRotate.td
+++ b/llvm/lib/Target/X86/X86InstrShiftRotate.td
@@ -879,6 +879,26 @@ let Predicates = [HasBMI2, HasEGPR, In64BitMode] in {
defm SHLX64 : bmi_shift<"shlx{q}", GR64, i64mem, "_EVEX">, T8, PD, REX_W, EVEX;
}
+
+def immle16_8 : ImmLeaf<i8, [{
+ return Imm <= 16 - 8;
+}]>;
+def immle32_8 : ImmLeaf<i8, [{
+ return Imm <= 32 - 8;
+}]>;
+def immle64_8 : ImmLeaf<i8, [{
+ return Imm <= 64 - 8;
+}]>;
+def immle32_16 : ImmLeaf<i8, [{
+ return Imm <= 32 - 16;
+}]>;
+def immle64_16 : ImmLeaf<i8, [{
+ return Imm <= 64 - 16;
+}]>;
+def immle64_32 : ImmLeaf<i8, [{
+ return Imm <= 64 - 32;
+}]>;
+
let Predicates = [HasBMI2] in {
// Prefer RORX which is non-destructive and doesn't update EFLAGS.
let AddedComplexity = 10 in {
@@ -891,6 +911,64 @@ let Predicates = [HasBMI2] in {
(RORX32ri GR32:$src, (ROT32L2R_imm8 imm:$shamt))>;
def : Pat<(rotl GR64:$src, (i8 imm:$shamt)),
(RORX64ri GR64:$src, (ROT64L2R_imm8 imm:$shamt))>;
+
+ // A right shift by less than a smaller register size that is then
+ // truncated to that register size can be replaced by RORX to
+ // preserve flags with the same execution cost
+
+ def : Pat<(i8 (trunc (srl GR16:$src, (i8 immle16_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
+ def : Pat<(i8 (trunc (sra GR16:$src, (i8 immle16_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
+ def : Pat<(i8 (trunc (srl GR32:$src, (i8 immle32_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
+ def : Pat<(i8 (trunc (sra GR32:$src, (i8 immle32_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
+ def : Pat<(i8 (trunc (srl GR64:$src, (i8 immle64_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
+ def : Pat<(i8 (trunc (sra GR64:$src, (i8 immle64_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
+
+
+ def : Pat<(i16 (trunc (srl GR32:$src, (i8 immle32_16:$shamt)))),
+ (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
+ def : Pat<(i16 (trunc (sra GR32:$src, (i8 immle32_16:$shamt)))),
+ (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
+ def : Pat<(i16 (trunc (srl GR64:$src, (i8 immle64_16:$shamt)))),
+ (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
+ def : Pat<(i16 (trunc (sra GR64:$src, (i8 immle64_16:$shamt)))),
+ (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
+
+ def : Pat<(i32 (trunc (srl GR64:$src, (i8 immle64_32:$shamt)))),
+ (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
+ def : Pat<(i32 (trunc (sra GR64:$src, (i8 immle64_32:$shamt)))),
+ (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
+
+
+ // Can't expand the load
+ def : Pat<(i8 (trunc (srl (loadi32 addr:$src), (i8 immle32_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
+ def : Pat<(i8 (trunc (sra (loadi32 addr:$src), (i8 immle32_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
+ def : Pat<(i8 (trunc (srl (loadi64 addr:$src), (i8 immle64_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
+ def : Pat<(i8 (trunc (sra (loadi64 addr:$src), (i8 immle64_8:$shamt)))),
+ (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
+
+
+ def : Pat<(i16 (trunc (srl (loadi32 addr:$src), (i8 immle32_16:$shamt)))),
+ (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
+ def : Pat<(i16 (trunc (sra (loadi32 addr:$src), (i8 immle32_16:$shamt)))),
+ (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
+ def : Pat<(i16 (trunc (srl (loadi64 addr:$src), (i8 immle64_16:$shamt)))),
+ (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
+ def : Pat<(i16 (trunc (sra (loadi64 addr:$src), (i8 immle64_16:$shamt)))),
+ (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
+
+ def : Pat<(i32 (trunc (srl (loadi64 addr:$src), (i8 immle64_32:$shamt)))),
+ (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
+ def : Pat<(i32 (trunc (sra (loadi64 addr:$src), (i8 immle64_32:$shamt)))),
+ (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
}
def : Pat<(rotr (loadi32 addr:$src), (i8 imm:$shamt)),
diff --git a/llvm/test/CodeGen/X86/atomic-unordered.ll b/llvm/test/CodeGen/X86/atomic-unordered.ll
index df123be53474f04..c867817fd2dfff7 100644
--- a/llvm/test/CodeGen/X86/atomic-unordered.ll
+++ b/llvm/test/CodeGen/X86/atomic-unordered.ll
@@ -2062,8 +2062,7 @@ define i32 @split_load(ptr %p) {
; CHECK-O3-LABEL: split_load:
; CHECK-O3: # %bb.0:
; CHECK-O3-NEXT: movq (%rdi), %rax
-; CHECK-O3-NEXT: movq %rax, %rcx
-; CHECK-O3-NEXT: shrq $32, %rcx
+; CHECK-O3-NEXT: rorxq $32, %rax, %rcx
; CHECK-O3-NEXT: orl %eax, %ecx
; CHECK-O3-NEXT: movzbl %cl, %eax
; CHECK-O3-NEXT: retq
diff --git a/llvm/test/CodeGen/X86/bmi2.ll b/llvm/test/CodeGen/X86/bmi2.ll
index 24e38cfeb704df4..e81434b35096ac6 100644
--- a/llvm/test/CodeGen/X86/bmi2.ll
+++ b/llvm/test/CodeGen/X86/bmi2.ll
@@ -310,8 +310,7 @@ define i32 @mulx32(i32 %x, i32 %y, ptr %p) {
; X64-NEXT: addl %edi, %edi
; X64-NEXT: leal (%rsi,%rsi), %eax
; X64-NEXT: imulq %rdi, %rax
-; X64-NEXT: movq %rax, %rcx
-; X64-NEXT: shrq $32, %rcx
+; X64-NEXT: rorxq $32, %rax, %rcx
; X64-NEXT: movl %ecx, (%rdx)
; X64-NEXT: # kill: def $eax killed $eax killed $rax
; X64-NEXT: retq
@@ -344,8 +343,7 @@ define i32 @mulx32_load(i32 %x, ptr %y, ptr %p) {
; X64-NEXT: leal (%rdi,%rdi), %eax
; X64-NEXT: movl (%rsi), %ecx
; X64-NEXT: imulq %rcx, %rax
-; X64-NEXT: movq %rax, %rcx
-; X64-NEXT: shrq $32, %rcx
+; X64-NEXT: rorxq $32, %rax, %rcx
; X64-NEXT: movl %ecx, (%rdx)
; X64-NEXT: # kill: def $eax killed $eax killed $rax
; X64-NEXT: retq
diff --git a/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll b/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
index 7996454a0158eac..a935bca3161b09f 100644
--- a/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
+++ b/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
@@ -157,7 +157,8 @@ define i1 @shr_to_shl_eq_i16_s1_fail(i16 %x) {
; CHECK: # %bb.0:
; CHECK-NEXT: movzwl %di, %eax
; CHECK-NEXT: andl $32766, %edi # imm = 0x7FFE
-; CHECK-NEXT: shrl %eax
+; CHECK-NOBMI-NEXT: shrl %eax
+; CHECK-BMI2-NEXT: rorxl $1, %eax, %eax
; CHECK-NEXT: cmpw %ax, %di
; CHECK-NEXT: sete %al
; CHECK-NEXT: retq
diff --git a/llvm/test/CodeGen/X86/pr35636.ll b/llvm/test/CodeGen/X86/pr35636.ll
index 0b7d64f38c78027..8b8a25eb5632c4d 100644
--- a/llvm/test/CodeGen/X86/pr35636.ll
+++ b/llvm/test/CodeGen/X86/pr35636.ll
@@ -10,7 +10,7 @@ define void @_Z15uint64_to_asciimPc(i64 %arg) {
; HSW-NEXT: mulxq %rax, %rax, %rax
; HSW-NEXT: shrq $42, %rax
; HSW-NEXT: imulq $281474977, %rax, %rax # imm = 0x10C6F7A1
-; HSW-NEXT: shrq $20, %rax
+; HSW-NEXT: rorxq $20, %rax, %rax
; HSW-NEXT: leal (%rax,%rax,4), %eax
; HSW-NEXT: addl $5, %eax
; HSW-NEXT: andl $134217727, %eax # imm = 0x7FFFFFF
@@ -27,7 +27,7 @@ define void @_Z15uint64_to_asciimPc(i64 %arg) {
; ZN-NEXT: mulxq %rax, %rax, %rax
; ZN-NEXT: shrq $42, %rax
; ZN-NEXT: imulq $281474977, %rax, %rax # imm = 0x10C6F7A1
-; ZN-NEXT: shrq $20, %rax
+; ZN-NEXT: rorxq $20, %rax, %rax
; ZN-NEXT: leal 5(%rax,%rax,4), %eax
; ZN-NEXT: andl $134217727, %eax # imm = 0x7FFFFFF
; ZN-NEXT: leal (%rax,%rax,4), %eax
diff --git a/llvm/test/CodeGen/X86/vector-trunc-ssat.ll b/llvm/test/CodeGen/X86/vector-trunc-ssat.ll
index 14f724fc3b8c79d..2837be16b6b2b02 100644
--- a/llvm/test/CodeGen/X86/vector-trunc-ssat.ll
+++ b/llvm/test/CodeGen/X86/vector-trunc-ssat.ll
@@ -4843,72 +4843,72 @@ define void @trunc_ssat_v16i32_v16i24(<16 x i32> %x, ptr %y) nounwind {
; SKX-NEXT: vpminsd {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm0, %zmm0
; SKX-NEXT: vpmaxsd {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm0, %zmm0
; SKX-NEXT: vextracti32x4 $3, %zmm0, %xmm1
-; SKX-NEXT: vpextrd $3, %xmm1, %r15d
-; SKX-NEXT: movw %r15w, 45(%rdi)
-; SKX-NEXT: vpextrd $2, %xmm1, %r14d
-; SKX-NEXT: movw %r14w, 42(%rdi)
-; SKX-NEXT: vpextrd $1, %xmm1, %ebp
-; SKX-NEXT: movw %bp, 39(%rdi)
+; SKX-NEXT: vpextrd $3, %xmm1, %r8d
+; SKX-NEXT: movw %r8w, 45(%rdi)
+; SKX-NEXT: vpextrd $2, %xmm1, %r9d
+; SKX-NEXT: movw %r9w, 42(%rdi)
+; SKX-NEXT: vpextrd $1, %xmm1, %r10d
+; SKX-NEXT: movw %r10w, 39(%rdi)
; SKX-NEXT: vmovd %xmm1, %r11d
; SKX-NEXT: movw %r11w, 36(%rdi)
; SKX-NEXT: vextracti32x4 $2, %zmm0, %xmm1
; SKX-NEXT: vpextrd $3, %xmm1, %ebx
; SKX-NEXT: movw %bx, 33(%rdi)
-; SKX-NEXT: vpextrd $2, %xmm1, %r10d
-; SKX-NEXT: movw %r10w, 30(%rdi)
-; SKX-NEXT: vpextrd $1, %xmm1, %r9d
-; SKX-NEXT: movw %r9w, 27(%rdi)
-; SKX-NEXT: vmovd %xmm1, %r8d
-; SKX-NEXT: vpextrd $3, %xmm0, %edx
-; SKX-NEXT: movw %r8w, 24(%rdi)
-; SKX-NEXT: movw %dx, 9(%rdi)
-; SKX-NEXT: vpextrd $2, %xmm0, %esi
-; SKX-NEXT: vpextrd $1, %xmm0, %eax
-; SKX-NEXT: movw %si, 6(%rdi)
-; SKX-NEXT: movw %ax, 3(%rdi)
-; SKX-NEXT: vmovd %xmm0, %ecx
-; SKX-NEXT: movw %cx, (%rdi)
-; SKX-NEXT: shrl $16, %r15d
-; SKX-NEXT: movb %r15b, 47(%rdi)
-; SKX-NEXT: shrl $16, %r14d
-; SKX-NEXT: movb %r14b, 44(%rdi)
-; SKX-NEXT: shrl $16, %ebp
-; SKX-NEXT: movb %bpl, 41(%rdi)
-; SKX-NEXT: shrl $16, %r11d
-; SKX-NEXT: movb %r11b, 38(%rdi)
-; SKX-NEXT: shrl $16, %ebx
-; SKX-NEXT: movb %bl, 35(%rdi)
-; SKX-NEXT: shrl $16, %r10d
-; SKX-NEXT: movb %r10b, 32(%rdi)
-; SKX-NEXT: shrl $16, %r9d
-; SKX-NEXT: movb %r9b, 29(%rdi)
-; SKX-NEXT: shrl $16, %r8d
+; SKX-NEXT: vpextrd $2, %xmm1, %ebp
+; SKX-NEXT: movw %bp, 30(%rdi)
+; SKX-NEXT: vpextrd $1, %xmm1, %r14d
+; SKX-NEXT: movw %r14w, 27(%rdi)
+; SKX-NEXT: vmovd %xmm1, %r15d
+; SKX-NEXT: vpextrd $3, %xmm0, %eax
+; SKX-NEXT: movw %r15w, 24(%rdi)
+; SKX-NEXT: movw %ax, 9(%rdi)
+; SKX-NEXT: vpextrd $2, %xmm0, %ecx
+; SKX-NEXT: vpextrd $1, %xmm0, %edx
+; SKX-NEXT: movw %cx, 6(%rdi)
+; SKX-NEXT: movw %dx, 3(%rdi)
+; SKX-NEXT: vmovd %xmm0, %esi
+; SKX-NEXT: movw %si, (%rdi)
+; SKX-NEXT: rorxl $16, %r8d, %r8d
+; SKX-NEXT: movb %r8b, 47(%rdi)
+; SKX-NEXT: rorxl $16, %r9d, %r8d
+; SKX-NEXT: movb %r8b, 44(%rdi)
+; SKX-NEXT: rorxl $16, %r10d, %r8d
+; SKX-NEXT: movb %r8b, 41(%rdi)
+; SKX-NEXT: rorxl $16, %r11d, %r8d
+; SKX-NEXT: movb %r8b, 38(%rdi)
+; SKX-NEXT: rorxl $16, %ebx, %r8d
+; SKX-NEXT: movb %r8b, 35(%rdi)
+; SKX-NEXT: rorxl $16, %ebp, %r8d
+; SKX-NEXT: movb %r8b, 32(%rdi)
+; SKX-NEXT: rorxl $16, %r14d, %r8d
+; SKX-NEXT: movb %r8b, 29(%rdi)
+; SKX-NEXT: rorxl $16, %r15d, %r8d
; SKX-NEXT: movb %r8b, 26(%rdi)
; SKX-NEXT: vextracti128 $1, %ymm0, %xmm0
-; SKX-NEXT: vpextrd $3, %xmm0, %r11d
-; SKX-NEXT: movw %r11w, 21(%rdi)
-; SKX-NEXT: vpextrd $2, %xmm0, %r10d
-; SKX-NEXT: movw %r10w, 18(%rdi)
-; SKX-NEXT: vpextrd $1, %xmm0, %r9d
-; SKX-NEXT: movw %r9w, 15(%rdi)
-; SKX-NEXT: vmovd %xmm0, %r8d
-; SKX-NEXT: movw %r8w, 12(%rdi)
-; SKX-NEXT: shrl $16, %edx
-; SKX-NEXT: movb %dl, 11(%rdi)
-; SKX-NEXT: shrl $16, %esi
-; SKX-NEXT: movb %sil, 8(%rdi)
-; SKX-NEXT: shrl $16, %eax
+; SKX-NEXT: vpextrd $3, %xmm0, %r8d
+; SKX-NEXT: movw %r8w, 21(%rdi)
+; SKX-NEXT: vpextrd $2, %xmm0, %r9d
+; SKX-NEXT: movw %r9w, 18(%rdi)
+; SKX-NEXT: vpextrd $1, %xmm0, %r10d
+; SKX-NEXT: movw %r10w, 15(%rdi)
+; SKX-NEXT: vmovd %xmm0, %r11d
+; SKX-NEXT: movw %r11w, 12(%rdi)
+; SKX-NEXT: rorxl $16, %eax, %eax
+; SKX-NEXT: movb %al, 11(%rdi)
+; SKX-NEXT: rorxl $16, %ecx, %eax
+; SKX-NEXT: movb %al, 8(%rdi)
+; SKX-NEXT: rorxl $16, %edx, %eax
; SKX-NEXT: movb %al, 5(%rdi)
-; SKX-NEXT: shrl $16, %ecx
-; SKX-NEXT: movb %cl, 2(%rdi)
-; SKX-NEXT: shrl $16, %r11d
-; SKX-NEXT: movb %r11b, 23(%rdi)
-; SKX-NEXT: shrl $16, %r10d
-; SKX-NEXT: movb %r10b, 20(%rdi)
-; SKX-NEXT: shrl $16, %r9d
-; SKX-NEXT: movb %r9b, 17(%rdi)
-; SKX-NEXT: shrl $16, %r8d
-; SKX-NEXT: movb %r8b, 14(%rdi)
+; SKX-NEXT: rorxl $16, %esi, %eax
+; SKX-NEXT: movb %al, 2(%rdi)
+; SKX-NEXT: rorxl $16, %r8d, %eax
+; SKX-NEXT: movb %al, 23(%rdi)
+; SKX-NEXT: rorxl $16, %r9d, %eax
+; SKX-NEXT: movb %al, 20(%rdi)
+; SKX-NEXT: rorxl $16, %r10d, %eax
+; SKX-NEXT: movb %al, 17(%rdi)
+; SKX-NEXT: rorxl $16, %r11d, %eax
+; SKX-NEXT: movb %al, 14(%rdi)
; SKX-NEXT: popq %rbx
; SKX-NEXT: popq %r14
; SKX-NEXT: popq %r15
>From 06342a51310156ce02296f81c44d42fc351ac4a4 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Fri, 12 Jan 2024 16:22:16 -0600
Subject: [PATCH 02/15] Change imm names
---
llvm/lib/Target/X86/X86InstrShiftRotate.td | 56 +++++++++++-----------
1 file changed, 28 insertions(+), 28 deletions(-)
diff --git a/llvm/lib/Target/X86/X86InstrShiftRotate.td b/llvm/lib/Target/X86/X86InstrShiftRotate.td
index 238e8e9b6e97f30..e294182a247ad6f 100644
--- a/llvm/lib/Target/X86/X86InstrShiftRotate.td
+++ b/llvm/lib/Target/X86/X86InstrShiftRotate.td
@@ -880,22 +880,22 @@ let Predicates = [HasBMI2, HasEGPR, In64BitMode] in {
}
-def immle16_8 : ImmLeaf<i8, [{
+def immle16minus8 : ImmLeaf<i8, [{
return Imm <= 16 - 8;
}]>;
-def immle32_8 : ImmLeaf<i8, [{
+def immle32minus8 : ImmLeaf<i8, [{
return Imm <= 32 - 8;
}]>;
-def immle64_8 : ImmLeaf<i8, [{
+def immle64minus8 : ImmLeaf<i8, [{
return Imm <= 64 - 8;
}]>;
-def immle32_16 : ImmLeaf<i8, [{
+def immle32minus16 : ImmLeaf<i8, [{
return Imm <= 32 - 16;
}]>;
-def immle64_16 : ImmLeaf<i8, [{
+def immle64minus16 : ImmLeaf<i8, [{
return Imm <= 64 - 16;
}]>;
-def immle64_32 : ImmLeaf<i8, [{
+def immle64minus32 : ImmLeaf<i8, [{
return Imm <= 64 - 32;
}]>;
@@ -916,58 +916,58 @@ let Predicates = [HasBMI2] in {
// truncated to that register size can be replaced by RORX to
// preserve flags with the same execution cost
- def : Pat<(i8 (trunc (srl GR16:$src, (i8 immle16_8:$shamt)))),
+ def : Pat<(i8 (trunc (srl GR16:$src, (i8 immle16minus8:$shamt)))),
(EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra GR16:$src, (i8 immle16_8:$shamt)))),
+ def : Pat<(i8 (trunc (sra GR16:$src, (i8 immle16minus8:$shamt)))),
(EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (srl GR32:$src, (i8 immle32_8:$shamt)))),
+ def : Pat<(i8 (trunc (srl GR32:$src, (i8 immle32minus8:$shamt)))),
(EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra GR32:$src, (i8 immle32_8:$shamt)))),
+ def : Pat<(i8 (trunc (sra GR32:$src, (i8 immle32minus8:$shamt)))),
(EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (srl GR64:$src, (i8 immle64_8:$shamt)))),
+ def : Pat<(i8 (trunc (srl GR64:$src, (i8 immle64minus8:$shamt)))),
(EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra GR64:$src, (i8 immle64_8:$shamt)))),
+ def : Pat<(i8 (trunc (sra GR64:$src, (i8 immle64minus8:$shamt)))),
(EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i16 (trunc (srl GR32:$src, (i8 immle32_16:$shamt)))),
+ def : Pat<(i16 (trunc (srl GR32:$src, (i8 immle32minus16:$shamt)))),
(EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (sra GR32:$src, (i8 immle32_16:$shamt)))),
+ def : Pat<(i16 (trunc (sra GR32:$src, (i8 immle32minus16:$shamt)))),
(EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (srl GR64:$src, (i8 immle64_16:$shamt)))),
+ def : Pat<(i16 (trunc (srl GR64:$src, (i8 immle64minus16:$shamt)))),
(EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (sra GR64:$src, (i8 immle64_16:$shamt)))),
+ def : Pat<(i16 (trunc (sra GR64:$src, (i8 immle64minus16:$shamt)))),
(EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i32 (trunc (srl GR64:$src, (i8 immle64_32:$shamt)))),
+ def : Pat<(i32 (trunc (srl GR64:$src, (i8 immle64minus32:$shamt)))),
(EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
- def : Pat<(i32 (trunc (sra GR64:$src, (i8 immle64_32:$shamt)))),
+ def : Pat<(i32 (trunc (sra GR64:$src, (i8 immle64minus32:$shamt)))),
(EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
// Can't expand the load
- def : Pat<(i8 (trunc (srl (loadi32 addr:$src), (i8 immle32_8:$shamt)))),
+ def : Pat<(i8 (trunc (srl (loadi32 addr:$src), (i8 immle32minus8:$shamt)))),
(EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra (loadi32 addr:$src), (i8 immle32_8:$shamt)))),
+ def : Pat<(i8 (trunc (sra (loadi32 addr:$src), (i8 immle32minus8:$shamt)))),
(EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (srl (loadi64 addr:$src), (i8 immle64_8:$shamt)))),
+ def : Pat<(i8 (trunc (srl (loadi64 addr:$src), (i8 immle64minus8:$shamt)))),
(EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra (loadi64 addr:$src), (i8 immle64_8:$shamt)))),
+ def : Pat<(i8 (trunc (sra (loadi64 addr:$src), (i8 immle64minus8:$shamt)))),
(EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i16 (trunc (srl (loadi32 addr:$src), (i8 immle32_16:$shamt)))),
+ def : Pat<(i16 (trunc (srl (loadi32 addr:$src), (i8 immle32minus16:$shamt)))),
(EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (sra (loadi32 addr:$src), (i8 immle32_16:$shamt)))),
+ def : Pat<(i16 (trunc (sra (loadi32 addr:$src), (i8 immle32minus16:$shamt)))),
(EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (srl (loadi64 addr:$src), (i8 immle64_16:$shamt)))),
+ def : Pat<(i16 (trunc (srl (loadi64 addr:$src), (i8 immle64minus16:$shamt)))),
(EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (sra (loadi64 addr:$src), (i8 immle64_16:$shamt)))),
+ def : Pat<(i16 (trunc (sra (loadi64 addr:$src), (i8 immle64minus16:$shamt)))),
(EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i32 (trunc (srl (loadi64 addr:$src), (i8 immle64_32:$shamt)))),
+ def : Pat<(i32 (trunc (srl (loadi64 addr:$src), (i8 immle64minus32:$shamt)))),
(EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
- def : Pat<(i32 (trunc (sra (loadi64 addr:$src), (i8 immle64_32:$shamt)))),
+ def : Pat<(i32 (trunc (sra (loadi64 addr:$src), (i8 immle64minus32:$shamt)))),
(EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
}
>From 777e5e2393f1c99865b1e0a4d1a734b11e8e00fb Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Fri, 12 Jan 2024 16:56:37 -0600
Subject: [PATCH 03/15] Add test
---
llvm/test/CodeGen/X86/pr77964.ll | 90 ++++++++++++++++++++++++++++++++
1 file changed, 90 insertions(+)
create mode 100644 llvm/test/CodeGen/X86/pr77964.ll
diff --git a/llvm/test/CodeGen/X86/pr77964.ll b/llvm/test/CodeGen/X86/pr77964.ll
new file mode 100644
index 000000000000000..4946d15fd80774d
--- /dev/null
+++ b/llvm/test/CodeGen/X86/pr77964.ll
@@ -0,0 +1,90 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefix=NOBMI
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+bmi2 | FileCheck %s --check-prefix=BMI
+
+declare { i32, i1 } @llvm.uadd.with.overflow.i32(i32, i32)
+declare { i16, i1 } @llvm.uadd.with.overflow.i16(i16, i16)
+
+define zeroext i16 @checksum(ptr %0) {
+; NOBMI-LABEL: checksum:
+; NOBMI: # %bb.0:
+; NOBMI-NEXT: movl (%rdi), %ecx
+; NOBMI-NEXT: addl 4(%rdi), %ecx
+; NOBMI-NEXT: adcl 8(%rdi), %ecx
+; NOBMI-NEXT: adcl 12(%rdi), %ecx
+; NOBMI-NEXT: adcl 16(%rdi), %ecx
+; NOBMI-NEXT: setb %dl
+; NOBMI-NEXT: movl %ecx, %eax
+; NOBMI-NEXT: shrl $16, %eax
+; NOBMI-NEXT: addb $255, %dl
+; NOBMI-NEXT: adcw %cx, %ax
+; NOBMI-NEXT: adcw $0, %ax
+; NOBMI-NEXT: notl %eax
+; NOBMI-NEXT: # kill: def $ax killed $ax killed $eax
+; NOBMI-NEXT: retq
+;
+; BMI-LABEL: checksum:
+; BMI: # %bb.0:
+; BMI-NEXT: movl (%rdi), %ecx
+; BMI-NEXT: addl 4(%rdi), %ecx
+; BMI-NEXT: adcl 8(%rdi), %ecx
+; BMI-NEXT: adcl 12(%rdi), %ecx
+; BMI-NEXT: adcl 16(%rdi), %ecx
+; BMI-NEXT: rorxl $16, %ecx, %eax
+; BMI-NEXT: adcw %cx, %ax
+; BMI-NEXT: adcw $0, %ax
+; BMI-NEXT: notl %eax
+; BMI-NEXT: # kill: def $ax killed $ax killed $eax
+; BMI-NEXT: retq
+ %2 = load i32, ptr %0
+ %3 = getelementptr inbounds i32, ptr %0, i64 1
+ %4 = load i32, ptr %3
+ %5 = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %2, i32 %4)
+ %6 = extractvalue { i32, i1 } %5, 1
+ %7 = extractvalue { i32, i1 } %5, 0
+ %8 = getelementptr inbounds i32, ptr %0, i64 2
+ %9 = load i32, ptr %8
+ %10 = zext i1 %6 to i32
+ %11 = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %7, i32 %9)
+ %12 = extractvalue { i32, i1 } %11, 1
+ %13 = extractvalue { i32, i1 } %11, 0
+ %14 = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %13, i32 %10)
+ %15 = extractvalue { i32, i1 } %14, 1
+ %16 = extractvalue { i32, i1 } %14, 0
+ %17 = or i1 %12, %15
+ %18 = getelementptr inbounds i32, ptr %0, i64 3
+ %19 = load i32, ptr %18
+ %20 = zext i1 %17 to i32
+ %21 = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %16, i32 %19)
+ %22 = extractvalue { i32, i1 } %21, 1
+ %23 = extractvalue { i32, i1 } %21, 0
+ %24 = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %23, i32 %20)
+ %25 = extractvalue { i32, i1 } %24, 1
+ %26 = extractvalue { i32, i1 } %24, 0
+ %27 = or i1 %22, %25
+ %28 = getelementptr inbounds i32, ptr %0, i64 4
+ %29 = load i32, ptr %28
+ %30 = zext i1 %27 to i32
+ %31 = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %26, i32 %29)
+ %32 = extractvalue { i32, i1 } %31, 1
+ %33 = extractvalue { i32, i1 } %31, 0
+ %34 = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %33, i32 %30)
+ %35 = extractvalue { i32, i1 } %34, 1
+ %36 = extractvalue { i32, i1 } %34, 0
+ %37 = or i1 %32, %35
+ %38 = zext i1 %37 to i16
+ %39 = trunc i32 %36 to i16
+ %40 = lshr i32 %36, 16
+ %41 = trunc i32 %40 to i16
+ %42 = call { i16, i1 } @llvm.uadd.with.overflow.i16(i16 %39, i16 %41)
+ %43 = extractvalue { i16, i1 } %42, 1
+ %44 = extractvalue { i16, i1 } %42, 0
+ %45 = call { i16, i1 } @llvm.uadd.with.overflow.i16(i16 %44, i16 %38)
+ %46 = extractvalue { i16, i1 } %45, 1
+ %47 = extractvalue { i16, i1 } %45, 0
+ %48 = or i1 %43, %46
+ %49 = zext i1 %48 to i16
+ %50 = add i16 %47, %49
+ %51 = xor i16 %50, -1
+ ret i16 %51
+}
>From bef5eaa2518594bc44bd2757d5e4d9527f5e7b8c Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce at brycemw.ca>
Date: Sat, 13 Jan 2024 15:26:53 -0600
Subject: [PATCH 04/15] Update test correctly
---
llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll b/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
index a935bca3161b09f..c74cae5fb345260 100644
--- a/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
+++ b/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
@@ -153,15 +153,23 @@ define i1 @shr_to_shl_eq_i16_s1(i16 %x) {
}
define i1 @shr_to_shl_eq_i16_s1_fail(i16 %x) {
-; CHECK-LABEL: shr_to_shl_eq_i16_s1_fail:
-; CHECK: # %bb.0:
-; CHECK-NEXT: movzwl %di, %eax
-; CHECK-NEXT: andl $32766, %edi # imm = 0x7FFE
+; CHECK-NOBMI-LABEL: shr_to_shl_eq_i16_s1_fail:
+; CHECK-NOBMI: # %bb.0:
+; CHECK-NOBMI-NEXT: movzwl %di, %eax
+; CHECK-NOBMI-NEXT: andl $32766, %edi # imm = 0x7FFE
; CHECK-NOBMI-NEXT: shrl %eax
+; CHECK-NOBMI-NEXT: cmpw %ax, %di
+; CHECK-NOBMI-NEXT: sete %al
+; CHECK-NOBMI-NEXT: retq
+;
+; CHECK-BMI2-LABEL: shr_to_shl_eq_i16_s1_fail:
+; CHECK-BMI2: # %bb.0:
+; CHECK-BMI2-NEXT: movzwl %di, %eax
+; CHECK-BMI2-NEXT: andl $32766, %edi # imm = 0x7FFE
; CHECK-BMI2-NEXT: rorxl $1, %eax, %eax
-; CHECK-NEXT: cmpw %ax, %di
-; CHECK-NEXT: sete %al
-; CHECK-NEXT: retq
+; CHECK-BMI2-NEXT: cmpw %ax, %di
+; CHECK-BMI2-NEXT: sete %al
+; CHECK-BMI2-NEXT: retq
%and = and i16 %x, 32766
%shr = lshr i16 %x, 1
%r = icmp eq i16 %and, %shr
>From d65d1854c71d7a7b99b6efd403dfc955c70a0741 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce at brycemw.ca>
Date: Sat, 13 Jan 2024 15:37:49 -0600
Subject: [PATCH 05/15] Add another test with memory
---
llvm/test/CodeGen/X86/pr77964.ll | 36 ++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/llvm/test/CodeGen/X86/pr77964.ll b/llvm/test/CodeGen/X86/pr77964.ll
index 4946d15fd80774d..df20e204790eeb6 100644
--- a/llvm/test/CodeGen/X86/pr77964.ll
+++ b/llvm/test/CodeGen/X86/pr77964.ll
@@ -88,3 +88,39 @@ define zeroext i16 @checksum(ptr %0) {
%51 = xor i16 %50, -1
ret i16 %51
}
+
+; This is expected to just load the byte and not use rorx
+define i8 @extract_aligned_byte(ptr %0) {
+; NOBMI-LABEL: extract_aligned_byte:
+; NOBMI: # %bb.0:
+; NOBMI-NEXT: movzbl 6(%rdi), %eax
+; NOBMI-NEXT: retq
+;
+; BMI-LABEL: extract_aligned_byte:
+; BMI: # %bb.0:
+; BMI-NEXT: movzbl 6(%rdi), %eax
+; BMI-NEXT: retq
+ %2 = load i64, ptr %0
+ %3 = lshr i64 %2, 48
+ %4 = trunc i64 %3 to i8
+ ret i8 %4
+}
+
+define i8 @extract_unaligned_byte(ptr %0) {
+; NOBMI-LABEL: extract_unaligned_byte:
+; NOBMI: # %bb.0:
+; NOBMI-NEXT: movq (%rdi), %rax
+; NOBMI-NEXT: shrq $52, %rax
+; NOBMI-NEXT: # kill: def $al killed $al killed $rax
+; NOBMI-NEXT: retq
+;
+; BMI-LABEL: extract_unaligned_byte:
+; BMI: # %bb.0:
+; BMI-NEXT: rorxq $52, (%rdi), %rax
+; BMI-NEXT: # kill: def $al killed $al killed $rax
+; BMI-NEXT: retq
+ %2 = load i64, ptr %0
+ %3 = lshr i64 %2, 52
+ %4 = trunc i64 %3 to i8
+ ret i8 %4
+}
>From 9a2c538f106ab524b9ad5ca5ce0d202da5924713 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce at brycemw.ca>
Date: Sat, 13 Jan 2024 20:11:35 -0600
Subject: [PATCH 06/15] Fix nits
Signed-off-by: Bryce Wilson <bryce at brycemw.ca>
---
llvm/lib/Target/X86/X86InstrShiftRotate.td | 2 +-
llvm/test/CodeGen/X86/pr77964.ll | 19 +++++++------------
2 files changed, 8 insertions(+), 13 deletions(-)
diff --git a/llvm/lib/Target/X86/X86InstrShiftRotate.td b/llvm/lib/Target/X86/X86InstrShiftRotate.td
index e294182a247ad6f..4c292ff2666101f 100644
--- a/llvm/lib/Target/X86/X86InstrShiftRotate.td
+++ b/llvm/lib/Target/X86/X86InstrShiftRotate.td
@@ -914,7 +914,7 @@ let Predicates = [HasBMI2] in {
// A right shift by less than a smaller register size that is then
// truncated to that register size can be replaced by RORX to
- // preserve flags with the same execution cost
+ // preserve flags with the same execution cost.
def : Pat<(i8 (trunc (srl GR16:$src, (i8 immle16minus8:$shamt)))),
(EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
diff --git a/llvm/test/CodeGen/X86/pr77964.ll b/llvm/test/CodeGen/X86/pr77964.ll
index df20e204790eeb6..e58e110e8bb2069 100644
--- a/llvm/test/CodeGen/X86/pr77964.ll
+++ b/llvm/test/CodeGen/X86/pr77964.ll
@@ -1,6 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefix=NOBMI
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+bmi2 | FileCheck %s --check-prefix=BMI
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefixes=CHECK,NOBMI
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+bmi2 | FileCheck %s --check-prefixes=CHECK,BMI
declare { i32, i1 } @llvm.uadd.with.overflow.i32(i32, i32)
declare { i16, i1 } @llvm.uadd.with.overflow.i16(i16, i16)
@@ -89,17 +89,12 @@ define zeroext i16 @checksum(ptr %0) {
ret i16 %51
}
-; This is expected to just load the byte and not use rorx
+; This is expected to just load the byte and not use rorx.
define i8 @extract_aligned_byte(ptr %0) {
-; NOBMI-LABEL: extract_aligned_byte:
-; NOBMI: # %bb.0:
-; NOBMI-NEXT: movzbl 6(%rdi), %eax
-; NOBMI-NEXT: retq
-;
-; BMI-LABEL: extract_aligned_byte:
-; BMI: # %bb.0:
-; BMI-NEXT: movzbl 6(%rdi), %eax
-; BMI-NEXT: retq
+; CHECK-LABEL: extract_aligned_byte:
+; CHECK: # %bb.0:
+; CHECK-NEXT: movzbl 6(%rdi), %eax
+; CHECK-NEXT: retq
%2 = load i64, ptr %0
%3 = lshr i64 %2, 48
%4 = trunc i64 %3 to i8
>From 8a4753177d47dbac3ce6a679065d7a11343a69c5 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce at brycemw.ca>
Date: Thu, 18 Jan 2024 07:54:54 -0600
Subject: [PATCH 07/15] Move conversion to a different place (profitability
check not in yet)
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 83 +++++++++++++++++
llvm/lib/Target/X86/X86InstrShiftRotate.td | 100 ++++++++++-----------
2 files changed, 133 insertions(+), 50 deletions(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 53ce720be2da4cc..09724363e165fab 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -554,6 +554,7 @@ namespace {
bool matchBitExtract(SDNode *Node);
bool shrinkAndImmediate(SDNode *N);
bool isMaskZeroExtended(SDNode *N) const;
+ bool rightShiftUncloberFlags(SDNode *N);
bool tryShiftAmountMod(SDNode *N);
bool tryShrinkShlLogicImm(SDNode *N);
bool tryVPTERNLOG(SDNode *N);
@@ -4208,6 +4209,84 @@ MachineSDNode *X86DAGToDAGISel::emitPCMPESTR(unsigned ROpc, unsigned MOpc,
return CNode;
}
+// When the consumer of a right shift (arithmetic or logical) wouldn't
+// notice the difference if the instruction was a rotate right instead
+// (because the bits shifted in are truncated away), the shift can be
+// replaced by the RORX instruction from BMI2. This doesn't set flags and
+// can output to a different register. This increases code size in most
+// cases, can have a false dependency when promoting the operand size,
+// and doesn't leave the high bits in a useful state. There may be other
+// situations where this transformation is profitable given those
+// conditions, but currently the transformation is only made when it
+// avoids spilling flags.
+bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
+ EVT VT = N->getValueType(0);
+
+ printf("Evaluating\n");
+
+ // Target has to have BMI2 for RORX
+ if (!Subtarget->hasBMI2())
+ return false;
+
+ printf("Has BMI2\n");
+
+ // Only handle scalar shifts.
+ if (VT.isVector())
+ return false;
+
+ printf("Not vector\n");
+
+ unsigned OpSize;
+ if (VT == MVT::i64) OpSize = 64;
+ else if (VT == MVT::i32) OpSize = 32;
+ else if (VT == MVT::i16) OpSize = 16;
+ else if (VT == MVT::i8) return false; // i8 shift can't be truncated.
+ else llvm_unreachable("Unexpected shift size");
+
+ printf("Good OpSize\n");
+
+ unsigned TruncateSize = 0;
+ // This only works when the result is truncated.
+ for (const SDNode *User : N->uses()) {
+ //printf("Looking at a use. TargetOpcode is %u\n", User->isTargetOpcode());
+ auto name = User->getOperationName(CurDAG);
+ printf("Looking at a thing %s %u %u\n", name.c_str(), User->getOpcode(), TargetOpcode::EXTRACT_SUBREG);
+ if (User->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
+ return false;
+ printf("It's an EXTRACT_SUBREG\n");
+ EVT TuncateType = User->getValueType(0);
+ if (TuncateType == MVT::i32) TruncateSize = std::max(TruncateSize, 32U);
+ else if (TuncateType == MVT::i16) TruncateSize = std::max(TruncateSize, 16U);
+ else if (TuncateType == MVT::i8) TruncateSize = std::max(TruncateSize, 8U);
+ else return false;
+ }
+ printf("Truncates are fine\n");
+ if (TruncateSize >= OpSize)
+ return false;
+ printf("Truncate size works\n");
+
+ // The shift must be by an immediate that wouldn't expose the zero or sign
+ // extended result.
+ auto *ShiftAmount = dyn_cast<ConstantSDNode>(N->getOperand(1));
+ if (!ShiftAmount || ShiftAmount->getZExtValue() > OpSize - TruncateSize)
+ return false;
+ printf("Shift amount is good\n");
+
+ // Only make the replacement when it avoids clobbering used flags. If it is
+ // determined to be profitable in other situations in the future, add those
+ // checks here.
+
+ // Make the replacement.
+ SDLoc DL(N);
+ MVT RotateSize = OpSize == 64 ? MVT::i64 : MVT::i32;
+ SDNode* Replacement = CurDAG->getNode(ISD::ROTR, DL, RotateSize, N->getOperand(0), N->getOperand(1)).getNode();
+ ReplaceNode(N, Replacement);
+ CurDAG->RemoveDeadNode(N);
+ SelectCode(Replacement);
+ printf("Replacement made\n");
+ return true;
+}
+
bool X86DAGToDAGISel::tryShiftAmountMod(SDNode *N) {
EVT VT = N->getValueType(0);
@@ -5227,6 +5306,10 @@ void X86DAGToDAGISel::Select(SDNode *Node) {
return;
[[fallthrough]];
case ISD::SRA:
+ printf("Going to evaluate SRL or SRA");
+ if (rightShiftUncloberFlags(Node))
+ return;
+ [[fallthrough]];
case ISD::SHL:
if (tryShiftAmountMod(Node))
return;
diff --git a/llvm/lib/Target/X86/X86InstrShiftRotate.td b/llvm/lib/Target/X86/X86InstrShiftRotate.td
index 4c292ff2666101f..42bda8e878d0037 100644
--- a/llvm/lib/Target/X86/X86InstrShiftRotate.td
+++ b/llvm/lib/Target/X86/X86InstrShiftRotate.td
@@ -916,59 +916,59 @@ let Predicates = [HasBMI2] in {
// truncated to that register size can be replaced by RORX to
// preserve flags with the same execution cost.
- def : Pat<(i8 (trunc (srl GR16:$src, (i8 immle16minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra GR16:$src, (i8 immle16minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (srl GR32:$src, (i8 immle32minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra GR32:$src, (i8 immle32minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (srl GR64:$src, (i8 immle64minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra GR64:$src, (i8 immle64minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
-
-
- def : Pat<(i16 (trunc (srl GR32:$src, (i8 immle32minus16:$shamt)))),
- (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (sra GR32:$src, (i8 immle32minus16:$shamt)))),
- (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (srl GR64:$src, (i8 immle64minus16:$shamt)))),
- (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (sra GR64:$src, (i8 immle64minus16:$shamt)))),
- (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
-
- def : Pat<(i32 (trunc (srl GR64:$src, (i8 immle64minus32:$shamt)))),
- (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
- def : Pat<(i32 (trunc (sra GR64:$src, (i8 immle64minus32:$shamt)))),
- (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
+// def : Pat<(i8 (trunc (srl GR16:$src, (i8 immle16minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
+// def : Pat<(i8 (trunc (sra GR16:$src, (i8 immle16minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
+// def : Pat<(i8 (trunc (srl GR32:$src, (i8 immle32minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
+// def : Pat<(i8 (trunc (sra GR32:$src, (i8 immle32minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
+// def : Pat<(i8 (trunc (srl GR64:$src, (i8 immle64minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
+// def : Pat<(i8 (trunc (sra GR64:$src, (i8 immle64minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
+
+
+// def : Pat<(i16 (trunc (srl GR32:$src, (i8 immle32minus16:$shamt)))),
+// (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
+// def : Pat<(i16 (trunc (sra GR32:$src, (i8 immle32minus16:$shamt)))),
+// (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
+// def : Pat<(i16 (trunc (srl GR64:$src, (i8 immle64minus16:$shamt)))),
+// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
+// def : Pat<(i16 (trunc (sra GR64:$src, (i8 immle64minus16:$shamt)))),
+// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
+
+// def : Pat<(i32 (trunc (srl GR64:$src, (i8 immle64minus32:$shamt)))),
+// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
+// def : Pat<(i32 (trunc (sra GR64:$src, (i8 immle64minus32:$shamt)))),
+// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
// Can't expand the load
- def : Pat<(i8 (trunc (srl (loadi32 addr:$src), (i8 immle32minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra (loadi32 addr:$src), (i8 immle32minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (srl (loadi64 addr:$src), (i8 immle64minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
- def : Pat<(i8 (trunc (sra (loadi64 addr:$src), (i8 immle64minus8:$shamt)))),
- (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
-
-
- def : Pat<(i16 (trunc (srl (loadi32 addr:$src), (i8 immle32minus16:$shamt)))),
- (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (sra (loadi32 addr:$src), (i8 immle32minus16:$shamt)))),
- (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (srl (loadi64 addr:$src), (i8 immle64minus16:$shamt)))),
- (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
- def : Pat<(i16 (trunc (sra (loadi64 addr:$src), (i8 immle64minus16:$shamt)))),
- (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
-
- def : Pat<(i32 (trunc (srl (loadi64 addr:$src), (i8 immle64minus32:$shamt)))),
- (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
- def : Pat<(i32 (trunc (sra (loadi64 addr:$src), (i8 immle64minus32:$shamt)))),
- (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
+// def : Pat<(i8 (trunc (srl (loadi32 addr:$src), (i8 immle32minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
+// def : Pat<(i8 (trunc (sra (loadi32 addr:$src), (i8 immle32minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
+// def : Pat<(i8 (trunc (srl (loadi64 addr:$src), (i8 immle64minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
+// def : Pat<(i8 (trunc (sra (loadi64 addr:$src), (i8 immle64minus8:$shamt)))),
+// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
+
+
+// def : Pat<(i16 (trunc (srl (loadi32 addr:$src), (i8 immle32minus16:$shamt)))),
+// (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
+// def : Pat<(i16 (trunc (sra (loadi32 addr:$src), (i8 immle32minus16:$shamt)))),
+// (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
+// def : Pat<(i16 (trunc (srl (loadi64 addr:$src), (i8 immle64minus16:$shamt)))),
+// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
+// def : Pat<(i16 (trunc (sra (loadi64 addr:$src), (i8 immle64minus16:$shamt)))),
+// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
+
+// def : Pat<(i32 (trunc (srl (loadi64 addr:$src), (i8 immle64minus32:$shamt)))),
+// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
+// def : Pat<(i32 (trunc (sra (loadi64 addr:$src), (i8 immle64minus32:$shamt)))),
+// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
}
def : Pat<(rotr (loadi32 addr:$src), (i8 imm:$shamt)),
>From 78eeeab5ef31bd51053d294ae8ef64e0af6cd085 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Thu, 18 Jan 2024 08:27:41 -0600
Subject: [PATCH 08/15] Fix clang-format, remove test prints
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 40 ++++++-----
llvm/lib/Target/X86/X86InstrShiftRotate.td | 78 ----------------------
2 files changed, 22 insertions(+), 96 deletions(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 09724363e165fab..406dadc29b38967 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -4237,40 +4237,43 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
printf("Not vector\n");
unsigned OpSize;
- if (VT == MVT::i64) OpSize = 64;
- else if (VT == MVT::i32) OpSize = 32;
- else if (VT == MVT::i16) OpSize = 16;
- else if (VT == MVT::i8) return false; // i8 shift can't be truncated.
- else llvm_unreachable("Unexpected shift size");
+ if (VT == MVT::i64)
+ OpSize = 64;
+ else if (VT == MVT::i32)
+ OpSize = 32;
+ else if (VT == MVT::i16)
+ OpSize = 16;
+ else if (VT == MVT::i8)
+ return false; // i8 shift can't be truncated.
+ else
+ llvm_unreachable("Unexpected shift size");
printf("Good OpSize\n");
unsigned TruncateSize = 0;
// This only works when the result is truncated.
for (const SDNode *User : N->uses()) {
- //printf("Looking at a use. TargetOpcode is %u\n", User->isTargetOpcode());
auto name = User->getOperationName(CurDAG);
- printf("Looking at a thing %s %u %u\n", name.c_str(), User->getOpcode(), TargetOpcode::EXTRACT_SUBREG);
if (User->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
return false;
- printf("It's an EXTRACT_SUBREG\n");
EVT TuncateType = User->getValueType(0);
- if (TuncateType == MVT::i32) TruncateSize = std::max(TruncateSize, 32U);
- else if (TuncateType == MVT::i16) TruncateSize = std::max(TruncateSize, 16U);
- else if (TuncateType == MVT::i8) TruncateSize = std::max(TruncateSize, 8U);
- else return false;
+ if (TuncateType == MVT::i32)
+ TruncateSize = std::max(TruncateSize, 32U);
+ else if (TuncateType == MVT::i16)
+ TruncateSize = std::max(TruncateSize, 16U);
+ else if (TuncateType == MVT::i8)
+ TruncateSize = std::max(TruncateSize, 8U);
+ else
+ return false;
}
- printf("Truncates are fine\n");
if (TruncateSize >= OpSize)
return false;
- printf("Truncate size works\n");
// The shift must be by an immediate that wouldn't expose the zero or sign
// extended result.
auto *ShiftAmount = dyn_cast<ConstantSDNode>(N->getOperand(1));
if (!ShiftAmount || ShiftAmount->getZExtValue() > OpSize - TruncateSize)
return false;
- printf("Shift amount is good\n");
// Only make the replacement when it avoids clobbering used flags. If it is
// determined to be profitable in other situations in the future, add those
@@ -4279,11 +4282,13 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
// Make the replacement.
SDLoc DL(N);
MVT RotateSize = OpSize == 64 ? MVT::i64 : MVT::i32;
- SDNode* Replacement = CurDAG->getNode(ISD::ROTR, DL, RotateSize, N->getOperand(0), N->getOperand(1)).getNode();
+ SDNode *Replacement = CurDAG
+ ->getNode(ISD::ROTR, DL, RotateSize,
+ N->getOperand(0), N->getOperand(1))
+ .getNode();
ReplaceNode(N, Replacement);
CurDAG->RemoveDeadNode(N);
SelectCode(Replacement);
- printf("Replacement made\n");
return true;
}
@@ -5306,7 +5311,6 @@ void X86DAGToDAGISel::Select(SDNode *Node) {
return;
[[fallthrough]];
case ISD::SRA:
- printf("Going to evaluate SRL or SRA");
if (rightShiftUncloberFlags(Node))
return;
[[fallthrough]];
diff --git a/llvm/lib/Target/X86/X86InstrShiftRotate.td b/llvm/lib/Target/X86/X86InstrShiftRotate.td
index 42bda8e878d0037..f951894db1890cd 100644
--- a/llvm/lib/Target/X86/X86InstrShiftRotate.td
+++ b/llvm/lib/Target/X86/X86InstrShiftRotate.td
@@ -879,26 +879,6 @@ let Predicates = [HasBMI2, HasEGPR, In64BitMode] in {
defm SHLX64 : bmi_shift<"shlx{q}", GR64, i64mem, "_EVEX">, T8, PD, REX_W, EVEX;
}
-
-def immle16minus8 : ImmLeaf<i8, [{
- return Imm <= 16 - 8;
-}]>;
-def immle32minus8 : ImmLeaf<i8, [{
- return Imm <= 32 - 8;
-}]>;
-def immle64minus8 : ImmLeaf<i8, [{
- return Imm <= 64 - 8;
-}]>;
-def immle32minus16 : ImmLeaf<i8, [{
- return Imm <= 32 - 16;
-}]>;
-def immle64minus16 : ImmLeaf<i8, [{
- return Imm <= 64 - 16;
-}]>;
-def immle64minus32 : ImmLeaf<i8, [{
- return Imm <= 64 - 32;
-}]>;
-
let Predicates = [HasBMI2] in {
// Prefer RORX which is non-destructive and doesn't update EFLAGS.
let AddedComplexity = 10 in {
@@ -911,64 +891,6 @@ let Predicates = [HasBMI2] in {
(RORX32ri GR32:$src, (ROT32L2R_imm8 imm:$shamt))>;
def : Pat<(rotl GR64:$src, (i8 imm:$shamt)),
(RORX64ri GR64:$src, (ROT64L2R_imm8 imm:$shamt))>;
-
- // A right shift by less than a smaller register size that is then
- // truncated to that register size can be replaced by RORX to
- // preserve flags with the same execution cost.
-
-// def : Pat<(i8 (trunc (srl GR16:$src, (i8 immle16minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
-// def : Pat<(i8 (trunc (sra GR16:$src, (i8 immle16minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX32ri (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, sub_16bit), imm:$shamt), sub_8bit)>;
-// def : Pat<(i8 (trunc (srl GR32:$src, (i8 immle32minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
-// def : Pat<(i8 (trunc (sra GR32:$src, (i8 immle32minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_8bit)>;
-// def : Pat<(i8 (trunc (srl GR64:$src, (i8 immle64minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
-// def : Pat<(i8 (trunc (sra GR64:$src, (i8 immle64minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_8bit)>;
-
-
-// def : Pat<(i16 (trunc (srl GR32:$src, (i8 immle32minus16:$shamt)))),
-// (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
-// def : Pat<(i16 (trunc (sra GR32:$src, (i8 immle32minus16:$shamt)))),
-// (EXTRACT_SUBREG (RORX32ri GR32:$src, imm:$shamt), sub_16bit)>;
-// def : Pat<(i16 (trunc (srl GR64:$src, (i8 immle64minus16:$shamt)))),
-// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
-// def : Pat<(i16 (trunc (sra GR64:$src, (i8 immle64minus16:$shamt)))),
-// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_16bit)>;
-
-// def : Pat<(i32 (trunc (srl GR64:$src, (i8 immle64minus32:$shamt)))),
-// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
-// def : Pat<(i32 (trunc (sra GR64:$src, (i8 immle64minus32:$shamt)))),
-// (EXTRACT_SUBREG (RORX64ri GR64:$src, imm:$shamt), sub_32bit)>;
-
-
- // Can't expand the load
-// def : Pat<(i8 (trunc (srl (loadi32 addr:$src), (i8 immle32minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
-// def : Pat<(i8 (trunc (sra (loadi32 addr:$src), (i8 immle32minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_8bit)>;
-// def : Pat<(i8 (trunc (srl (loadi64 addr:$src), (i8 immle64minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
-// def : Pat<(i8 (trunc (sra (loadi64 addr:$src), (i8 immle64minus8:$shamt)))),
-// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_8bit)>;
-
-
-// def : Pat<(i16 (trunc (srl (loadi32 addr:$src), (i8 immle32minus16:$shamt)))),
-// (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
-// def : Pat<(i16 (trunc (sra (loadi32 addr:$src), (i8 immle32minus16:$shamt)))),
-// (EXTRACT_SUBREG (RORX32mi addr:$src, imm:$shamt), sub_16bit)>;
-// def : Pat<(i16 (trunc (srl (loadi64 addr:$src), (i8 immle64minus16:$shamt)))),
-// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
-// def : Pat<(i16 (trunc (sra (loadi64 addr:$src), (i8 immle64minus16:$shamt)))),
-// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_16bit)>;
-
-// def : Pat<(i32 (trunc (srl (loadi64 addr:$src), (i8 immle64minus32:$shamt)))),
-// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
-// def : Pat<(i32 (trunc (sra (loadi64 addr:$src), (i8 immle64minus32:$shamt)))),
-// (EXTRACT_SUBREG (RORX64mi addr:$src, imm:$shamt), sub_32bit)>;
}
def : Pat<(rotr (loadi32 addr:$src), (i8 imm:$shamt)),
>From 43a0910fc3afbcccd270cd55aa390a47be358799 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Tue, 23 Jan 2024 11:47:34 -0600
Subject: [PATCH 09/15] Add proper profitability check
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 48 +++++----
llvm/test/CodeGen/X86/atomic-unordered.ll | 3 +-
llvm/test/CodeGen/X86/bmi2.ll | 6 +-
llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll | 25 ++---
llvm/test/CodeGen/X86/pr35636.ll | 4 +-
llvm/test/CodeGen/X86/pr77964.ll | 18 ++--
llvm/test/CodeGen/X86/vector-trunc-ssat.ll | 116 ++++++++++-----------
7 files changed, 107 insertions(+), 113 deletions(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 73085dd6b82b5e4..d6b6ce653f8ed78 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -4213,33 +4213,25 @@ MachineSDNode *X86DAGToDAGISel::emitPCMPESTR(unsigned ROpc, unsigned MOpc,
return CNode;
}
-// When the consumer of a right shift (arithmetic or logical) wouldn't
-// notice the difference if the instruction was a rotate right instead
-// (because the bits shifted in are truncated away), the shift can be
-// replaced by the RORX instruction from BMI2. This doesn't set flags and
-// can output to a different register. This increases code size in most
-// cases, can have a false dependency when promoting the operand size,
-// and doesn't leave the high bits in a useful state. There may be other
-// situations where this transformation is profitable given those
-// conditions, but currently the transformation is only made when it
-// avoids spilling flags.
+// When the consumer of a right shift (arithmetic or logical) wouldn't notice
+// the difference if the instruction was a rotate right instead (because the
+// bits shifted in are truncated away), the shift can be replaced by the RORX
+// instruction from BMI2. This doesn't set flags and can output to a different
+// register. However, this increases code size in most cases, and doesn't leave
+// the high bits in a useful state. There may be other situations where this
+// transformation is profitable given those conditions, but currently the
+// transformation is only made when it likely avoids spilling flags.
bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
EVT VT = N->getValueType(0);
- printf("Evaluating\n");
-
// Target has to have BMI2 for RORX
if (!Subtarget->hasBMI2())
return false;
- printf("Has BMI2\n");
-
// Only handle scalar shifts.
if (VT.isVector())
return false;
- printf("Not vector\n");
-
unsigned OpSize;
if (VT == MVT::i64)
OpSize = 64;
@@ -4252,8 +4244,6 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
else
llvm_unreachable("Unexpected shift size");
- printf("Good OpSize\n");
-
unsigned TruncateSize = 0;
// This only works when the result is truncated.
for (const SDNode *User : N->uses()) {
@@ -4279,9 +4269,25 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
if (!ShiftAmount || ShiftAmount->getZExtValue() > OpSize - TruncateSize)
return false;
- // Only make the replacement when it avoids clobbering used flags. If it is
- // determined to be profitable in other situations in the future, add those
- // checks here.
+ // Only make the replacement when it avoids clobbering used flags. This is a
+ // similar heuristic as used in the conversion to LEA, namely looking at the
+ // operand for an instruction that creates flags where those flags are used.
+ // This will have both false positives and false negatives. Ideally, both of
+ // these happen later on. Perhaps in copy to flags lowering or in register
+ // allocation.
+ bool MightClobberFlags = false;
+ SDNode *Input = N->getOperand(0).getNode();
+ for (auto Use : Input->uses()) {
+ if (Use->getOpcode() == ISD::CopyToReg) {
+ auto RegisterNode = dyn_cast<RegisterSDNode>(Use->getOperand(1).getNode());
+ if (RegisterNode && RegisterNode->getReg() == X86::EFLAGS) {
+ MightClobberFlags = true;
+ break;
+ }
+ }
+ }
+ if (!MightClobberFlags)
+ return false;
// Make the replacement.
SDLoc DL(N);
diff --git a/llvm/test/CodeGen/X86/atomic-unordered.ll b/llvm/test/CodeGen/X86/atomic-unordered.ll
index c867817fd2dfff7..df123be53474f04 100644
--- a/llvm/test/CodeGen/X86/atomic-unordered.ll
+++ b/llvm/test/CodeGen/X86/atomic-unordered.ll
@@ -2062,7 +2062,8 @@ define i32 @split_load(ptr %p) {
; CHECK-O3-LABEL: split_load:
; CHECK-O3: # %bb.0:
; CHECK-O3-NEXT: movq (%rdi), %rax
-; CHECK-O3-NEXT: rorxq $32, %rax, %rcx
+; CHECK-O3-NEXT: movq %rax, %rcx
+; CHECK-O3-NEXT: shrq $32, %rcx
; CHECK-O3-NEXT: orl %eax, %ecx
; CHECK-O3-NEXT: movzbl %cl, %eax
; CHECK-O3-NEXT: retq
diff --git a/llvm/test/CodeGen/X86/bmi2.ll b/llvm/test/CodeGen/X86/bmi2.ll
index be37b62a2e236b0..cabeebb0c3f3669 100644
--- a/llvm/test/CodeGen/X86/bmi2.ll
+++ b/llvm/test/CodeGen/X86/bmi2.ll
@@ -406,7 +406,8 @@ define i32 @mulx32(i32 %x, i32 %y, ptr %p) {
; X64-NEXT: addl %edi, %edi
; X64-NEXT: leal (%rsi,%rsi), %eax
; X64-NEXT: imulq %rdi, %rax
-; X64-NEXT: rorxq $32, %rax, %rcx
+; X64-NEXT: movq %rax, %rcx
+; X64-NEXT: shrq $32, %rcx
; X64-NEXT: movl %ecx, (%rdx)
; X64-NEXT: # kill: def $eax killed $eax killed $rax
; X64-NEXT: retq
@@ -452,7 +453,8 @@ define i32 @mulx32_load(i32 %x, ptr %y, ptr %p) {
; X64-NEXT: leal (%rdi,%rdi), %eax
; X64-NEXT: movl (%rsi), %ecx
; X64-NEXT: imulq %rcx, %rax
-; X64-NEXT: rorxq $32, %rax, %rcx
+; X64-NEXT: movq %rax, %rcx
+; X64-NEXT: shrq $32, %rcx
; X64-NEXT: movl %ecx, (%rdx)
; X64-NEXT: # kill: def $eax killed $eax killed $rax
; X64-NEXT: retq
diff --git a/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll b/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
index c74cae5fb345260..7996454a0158eac 100644
--- a/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
+++ b/llvm/test/CodeGen/X86/cmp-shiftX-maskX.ll
@@ -153,23 +153,14 @@ define i1 @shr_to_shl_eq_i16_s1(i16 %x) {
}
define i1 @shr_to_shl_eq_i16_s1_fail(i16 %x) {
-; CHECK-NOBMI-LABEL: shr_to_shl_eq_i16_s1_fail:
-; CHECK-NOBMI: # %bb.0:
-; CHECK-NOBMI-NEXT: movzwl %di, %eax
-; CHECK-NOBMI-NEXT: andl $32766, %edi # imm = 0x7FFE
-; CHECK-NOBMI-NEXT: shrl %eax
-; CHECK-NOBMI-NEXT: cmpw %ax, %di
-; CHECK-NOBMI-NEXT: sete %al
-; CHECK-NOBMI-NEXT: retq
-;
-; CHECK-BMI2-LABEL: shr_to_shl_eq_i16_s1_fail:
-; CHECK-BMI2: # %bb.0:
-; CHECK-BMI2-NEXT: movzwl %di, %eax
-; CHECK-BMI2-NEXT: andl $32766, %edi # imm = 0x7FFE
-; CHECK-BMI2-NEXT: rorxl $1, %eax, %eax
-; CHECK-BMI2-NEXT: cmpw %ax, %di
-; CHECK-BMI2-NEXT: sete %al
-; CHECK-BMI2-NEXT: retq
+; CHECK-LABEL: shr_to_shl_eq_i16_s1_fail:
+; CHECK: # %bb.0:
+; CHECK-NEXT: movzwl %di, %eax
+; CHECK-NEXT: andl $32766, %edi # imm = 0x7FFE
+; CHECK-NEXT: shrl %eax
+; CHECK-NEXT: cmpw %ax, %di
+; CHECK-NEXT: sete %al
+; CHECK-NEXT: retq
%and = and i16 %x, 32766
%shr = lshr i16 %x, 1
%r = icmp eq i16 %and, %shr
diff --git a/llvm/test/CodeGen/X86/pr35636.ll b/llvm/test/CodeGen/X86/pr35636.ll
index 8b8a25eb5632c4d..0b7d64f38c78027 100644
--- a/llvm/test/CodeGen/X86/pr35636.ll
+++ b/llvm/test/CodeGen/X86/pr35636.ll
@@ -10,7 +10,7 @@ define void @_Z15uint64_to_asciimPc(i64 %arg) {
; HSW-NEXT: mulxq %rax, %rax, %rax
; HSW-NEXT: shrq $42, %rax
; HSW-NEXT: imulq $281474977, %rax, %rax # imm = 0x10C6F7A1
-; HSW-NEXT: rorxq $20, %rax, %rax
+; HSW-NEXT: shrq $20, %rax
; HSW-NEXT: leal (%rax,%rax,4), %eax
; HSW-NEXT: addl $5, %eax
; HSW-NEXT: andl $134217727, %eax # imm = 0x7FFFFFF
@@ -27,7 +27,7 @@ define void @_Z15uint64_to_asciimPc(i64 %arg) {
; ZN-NEXT: mulxq %rax, %rax, %rax
; ZN-NEXT: shrq $42, %rax
; ZN-NEXT: imulq $281474977, %rax, %rax # imm = 0x10C6F7A1
-; ZN-NEXT: rorxq $20, %rax, %rax
+; ZN-NEXT: shrq $20, %rax
; ZN-NEXT: leal 5(%rax,%rax,4), %eax
; ZN-NEXT: andl $134217727, %eax # imm = 0x7FFFFFF
; ZN-NEXT: leal (%rax,%rax,4), %eax
diff --git a/llvm/test/CodeGen/X86/pr77964.ll b/llvm/test/CodeGen/X86/pr77964.ll
index e58e110e8bb2069..f06f54c38f0039a 100644
--- a/llvm/test/CodeGen/X86/pr77964.ll
+++ b/llvm/test/CodeGen/X86/pr77964.ll
@@ -102,18 +102,12 @@ define i8 @extract_aligned_byte(ptr %0) {
}
define i8 @extract_unaligned_byte(ptr %0) {
-; NOBMI-LABEL: extract_unaligned_byte:
-; NOBMI: # %bb.0:
-; NOBMI-NEXT: movq (%rdi), %rax
-; NOBMI-NEXT: shrq $52, %rax
-; NOBMI-NEXT: # kill: def $al killed $al killed $rax
-; NOBMI-NEXT: retq
-;
-; BMI-LABEL: extract_unaligned_byte:
-; BMI: # %bb.0:
-; BMI-NEXT: rorxq $52, (%rdi), %rax
-; BMI-NEXT: # kill: def $al killed $al killed $rax
-; BMI-NEXT: retq
+; CHECK-LABEL: extract_unaligned_byte:
+; CHECK: # %bb.0:
+; CHECK-NEXT: movq (%rdi), %rax
+; CHECK-NEXT: shrq $52, %rax
+; CHECK-NEXT: # kill: def $al killed $al killed $rax
+; CHECK-NEXT: retq
%2 = load i64, ptr %0
%3 = lshr i64 %2, 52
%4 = trunc i64 %3 to i8
diff --git a/llvm/test/CodeGen/X86/vector-trunc-ssat.ll b/llvm/test/CodeGen/X86/vector-trunc-ssat.ll
index 2837be16b6b2b02..14f724fc3b8c79d 100644
--- a/llvm/test/CodeGen/X86/vector-trunc-ssat.ll
+++ b/llvm/test/CodeGen/X86/vector-trunc-ssat.ll
@@ -4843,72 +4843,72 @@ define void @trunc_ssat_v16i32_v16i24(<16 x i32> %x, ptr %y) nounwind {
; SKX-NEXT: vpminsd {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm0, %zmm0
; SKX-NEXT: vpmaxsd {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm0, %zmm0
; SKX-NEXT: vextracti32x4 $3, %zmm0, %xmm1
-; SKX-NEXT: vpextrd $3, %xmm1, %r8d
-; SKX-NEXT: movw %r8w, 45(%rdi)
-; SKX-NEXT: vpextrd $2, %xmm1, %r9d
-; SKX-NEXT: movw %r9w, 42(%rdi)
-; SKX-NEXT: vpextrd $1, %xmm1, %r10d
-; SKX-NEXT: movw %r10w, 39(%rdi)
+; SKX-NEXT: vpextrd $3, %xmm1, %r15d
+; SKX-NEXT: movw %r15w, 45(%rdi)
+; SKX-NEXT: vpextrd $2, %xmm1, %r14d
+; SKX-NEXT: movw %r14w, 42(%rdi)
+; SKX-NEXT: vpextrd $1, %xmm1, %ebp
+; SKX-NEXT: movw %bp, 39(%rdi)
; SKX-NEXT: vmovd %xmm1, %r11d
; SKX-NEXT: movw %r11w, 36(%rdi)
; SKX-NEXT: vextracti32x4 $2, %zmm0, %xmm1
; SKX-NEXT: vpextrd $3, %xmm1, %ebx
; SKX-NEXT: movw %bx, 33(%rdi)
-; SKX-NEXT: vpextrd $2, %xmm1, %ebp
-; SKX-NEXT: movw %bp, 30(%rdi)
-; SKX-NEXT: vpextrd $1, %xmm1, %r14d
-; SKX-NEXT: movw %r14w, 27(%rdi)
-; SKX-NEXT: vmovd %xmm1, %r15d
-; SKX-NEXT: vpextrd $3, %xmm0, %eax
-; SKX-NEXT: movw %r15w, 24(%rdi)
-; SKX-NEXT: movw %ax, 9(%rdi)
-; SKX-NEXT: vpextrd $2, %xmm0, %ecx
-; SKX-NEXT: vpextrd $1, %xmm0, %edx
-; SKX-NEXT: movw %cx, 6(%rdi)
-; SKX-NEXT: movw %dx, 3(%rdi)
-; SKX-NEXT: vmovd %xmm0, %esi
-; SKX-NEXT: movw %si, (%rdi)
-; SKX-NEXT: rorxl $16, %r8d, %r8d
-; SKX-NEXT: movb %r8b, 47(%rdi)
-; SKX-NEXT: rorxl $16, %r9d, %r8d
-; SKX-NEXT: movb %r8b, 44(%rdi)
-; SKX-NEXT: rorxl $16, %r10d, %r8d
-; SKX-NEXT: movb %r8b, 41(%rdi)
-; SKX-NEXT: rorxl $16, %r11d, %r8d
-; SKX-NEXT: movb %r8b, 38(%rdi)
-; SKX-NEXT: rorxl $16, %ebx, %r8d
-; SKX-NEXT: movb %r8b, 35(%rdi)
-; SKX-NEXT: rorxl $16, %ebp, %r8d
-; SKX-NEXT: movb %r8b, 32(%rdi)
-; SKX-NEXT: rorxl $16, %r14d, %r8d
-; SKX-NEXT: movb %r8b, 29(%rdi)
-; SKX-NEXT: rorxl $16, %r15d, %r8d
+; SKX-NEXT: vpextrd $2, %xmm1, %r10d
+; SKX-NEXT: movw %r10w, 30(%rdi)
+; SKX-NEXT: vpextrd $1, %xmm1, %r9d
+; SKX-NEXT: movw %r9w, 27(%rdi)
+; SKX-NEXT: vmovd %xmm1, %r8d
+; SKX-NEXT: vpextrd $3, %xmm0, %edx
+; SKX-NEXT: movw %r8w, 24(%rdi)
+; SKX-NEXT: movw %dx, 9(%rdi)
+; SKX-NEXT: vpextrd $2, %xmm0, %esi
+; SKX-NEXT: vpextrd $1, %xmm0, %eax
+; SKX-NEXT: movw %si, 6(%rdi)
+; SKX-NEXT: movw %ax, 3(%rdi)
+; SKX-NEXT: vmovd %xmm0, %ecx
+; SKX-NEXT: movw %cx, (%rdi)
+; SKX-NEXT: shrl $16, %r15d
+; SKX-NEXT: movb %r15b, 47(%rdi)
+; SKX-NEXT: shrl $16, %r14d
+; SKX-NEXT: movb %r14b, 44(%rdi)
+; SKX-NEXT: shrl $16, %ebp
+; SKX-NEXT: movb %bpl, 41(%rdi)
+; SKX-NEXT: shrl $16, %r11d
+; SKX-NEXT: movb %r11b, 38(%rdi)
+; SKX-NEXT: shrl $16, %ebx
+; SKX-NEXT: movb %bl, 35(%rdi)
+; SKX-NEXT: shrl $16, %r10d
+; SKX-NEXT: movb %r10b, 32(%rdi)
+; SKX-NEXT: shrl $16, %r9d
+; SKX-NEXT: movb %r9b, 29(%rdi)
+; SKX-NEXT: shrl $16, %r8d
; SKX-NEXT: movb %r8b, 26(%rdi)
; SKX-NEXT: vextracti128 $1, %ymm0, %xmm0
-; SKX-NEXT: vpextrd $3, %xmm0, %r8d
-; SKX-NEXT: movw %r8w, 21(%rdi)
-; SKX-NEXT: vpextrd $2, %xmm0, %r9d
-; SKX-NEXT: movw %r9w, 18(%rdi)
-; SKX-NEXT: vpextrd $1, %xmm0, %r10d
-; SKX-NEXT: movw %r10w, 15(%rdi)
-; SKX-NEXT: vmovd %xmm0, %r11d
-; SKX-NEXT: movw %r11w, 12(%rdi)
-; SKX-NEXT: rorxl $16, %eax, %eax
-; SKX-NEXT: movb %al, 11(%rdi)
-; SKX-NEXT: rorxl $16, %ecx, %eax
-; SKX-NEXT: movb %al, 8(%rdi)
-; SKX-NEXT: rorxl $16, %edx, %eax
+; SKX-NEXT: vpextrd $3, %xmm0, %r11d
+; SKX-NEXT: movw %r11w, 21(%rdi)
+; SKX-NEXT: vpextrd $2, %xmm0, %r10d
+; SKX-NEXT: movw %r10w, 18(%rdi)
+; SKX-NEXT: vpextrd $1, %xmm0, %r9d
+; SKX-NEXT: movw %r9w, 15(%rdi)
+; SKX-NEXT: vmovd %xmm0, %r8d
+; SKX-NEXT: movw %r8w, 12(%rdi)
+; SKX-NEXT: shrl $16, %edx
+; SKX-NEXT: movb %dl, 11(%rdi)
+; SKX-NEXT: shrl $16, %esi
+; SKX-NEXT: movb %sil, 8(%rdi)
+; SKX-NEXT: shrl $16, %eax
; SKX-NEXT: movb %al, 5(%rdi)
-; SKX-NEXT: rorxl $16, %esi, %eax
-; SKX-NEXT: movb %al, 2(%rdi)
-; SKX-NEXT: rorxl $16, %r8d, %eax
-; SKX-NEXT: movb %al, 23(%rdi)
-; SKX-NEXT: rorxl $16, %r9d, %eax
-; SKX-NEXT: movb %al, 20(%rdi)
-; SKX-NEXT: rorxl $16, %r10d, %eax
-; SKX-NEXT: movb %al, 17(%rdi)
-; SKX-NEXT: rorxl $16, %r11d, %eax
-; SKX-NEXT: movb %al, 14(%rdi)
+; SKX-NEXT: shrl $16, %ecx
+; SKX-NEXT: movb %cl, 2(%rdi)
+; SKX-NEXT: shrl $16, %r11d
+; SKX-NEXT: movb %r11b, 23(%rdi)
+; SKX-NEXT: shrl $16, %r10d
+; SKX-NEXT: movb %r10b, 20(%rdi)
+; SKX-NEXT: shrl $16, %r9d
+; SKX-NEXT: movb %r9b, 17(%rdi)
+; SKX-NEXT: shrl $16, %r8d
+; SKX-NEXT: movb %r8b, 14(%rdi)
; SKX-NEXT: popq %rbx
; SKX-NEXT: popq %r14
; SKX-NEXT: popq %r15
>From b14b08abba26d93726dec892ea64ed25d1ab217a Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Tue, 23 Jan 2024 11:57:18 -0600
Subject: [PATCH 10/15] clang-format
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index d6b6ce653f8ed78..5d90e748a6da644 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -4279,7 +4279,8 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
SDNode *Input = N->getOperand(0).getNode();
for (auto Use : Input->uses()) {
if (Use->getOpcode() == ISD::CopyToReg) {
- auto RegisterNode = dyn_cast<RegisterSDNode>(Use->getOperand(1).getNode());
+ auto RegisterNode =
+ dyn_cast<RegisterSDNode>(Use->getOperand(1).getNode());
if (RegisterNode && RegisterNode->getReg() == X86::EFLAGS) {
MightClobberFlags = true;
break;
>From 4f4dd7d3d14d557dc6bfb76b1f1388ebc94b2726 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Tue, 23 Jan 2024 12:19:26 -0600
Subject: [PATCH 11/15] Add pointer
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 5d90e748a6da644..63a7cf2efea0472 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -4279,7 +4279,7 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
SDNode *Input = N->getOperand(0).getNode();
for (auto Use : Input->uses()) {
if (Use->getOpcode() == ISD::CopyToReg) {
- auto RegisterNode =
+ auto *RegisterNode =
dyn_cast<RegisterSDNode>(Use->getOperand(1).getNode());
if (RegisterNode && RegisterNode->getReg() == X86::EFLAGS) {
MightClobberFlags = true;
>From a3ad2b5d9e7da4580f0b29ca313989978d605b5f Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Wed, 24 Jan 2024 16:24:02 -0600
Subject: [PATCH 12/15] Fix bug
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index fab2e131429daab..99a1470c60fbaec 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -4252,7 +4252,7 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
// This only works when the result is truncated.
for (const SDNode *User : N->uses()) {
auto name = User->getOperationName(CurDAG);
- if (User->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
+ if (!User.isMachineOpcode() || User->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
return false;
EVT TuncateType = User->getValueType(0);
if (TuncateType == MVT::i32)
>From afaff4ad61723e0dee1d9947068fff0b5bdc3fb4 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Wed, 24 Jan 2024 16:27:26 -0600
Subject: [PATCH 13/15] clang-format
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 99a1470c60fbaec..17a57f70b535461 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -4252,7 +4252,8 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
// This only works when the result is truncated.
for (const SDNode *User : N->uses()) {
auto name = User->getOperationName(CurDAG);
- if (!User.isMachineOpcode() || User->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
+ if (!User.isMachineOpcode() ||
+ User->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
return false;
EVT TuncateType = User->getValueType(0);
if (TuncateType == MVT::i32)
>From 349af52eba94bd69b298ed5b86a0ff1ef493a1fd Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Wed, 24 Jan 2024 16:43:28 -0600
Subject: [PATCH 14/15] typo
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 17a57f70b535461..f9d4edc7a8464a5 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -4252,7 +4252,7 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
// This only works when the result is truncated.
for (const SDNode *User : N->uses()) {
auto name = User->getOperationName(CurDAG);
- if (!User.isMachineOpcode() ||
+ if (!User->isMachineOpcode() ||
User->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
return false;
EVT TuncateType = User->getValueType(0);
>From 1c990b34374b8377b9dd223c6dd4d15f2eb1c140 Mon Sep 17 00:00:00 2001
From: Bryce Wilson <bryce.wilson at oldmissioncapital.com>
Date: Thu, 25 Jan 2024 08:57:01 -0600
Subject: [PATCH 15/15] Address comments
---
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index f9d4edc7a8464a5..028c49c0e4df648 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -554,7 +554,7 @@ namespace {
bool matchBitExtract(SDNode *Node);
bool shrinkAndImmediate(SDNode *N);
bool isMaskZeroExtended(SDNode *N) const;
- bool rightShiftUncloberFlags(SDNode *N);
+ bool rightShiftUnclobberFlags(SDNode *N);
bool tryShiftAmountMod(SDNode *N);
bool tryShrinkShlLogicImm(SDNode *N);
bool tryVPTERNLOG(SDNode *N);
@@ -4225,7 +4225,7 @@ MachineSDNode *X86DAGToDAGISel::emitPCMPESTR(unsigned ROpc, unsigned MOpc,
// the high bits in a useful state. There may be other situations where this
// transformation is profitable given those conditions, but currently the
// transformation is only made when it likely avoids spilling flags.
-bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
+bool X86DAGToDAGISel::rightShiftUnclobberFlags(SDNode *N) {
EVT VT = N->getValueType(0);
// Target has to have BMI2 for RORX
@@ -4251,7 +4251,6 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
unsigned TruncateSize = 0;
// This only works when the result is truncated.
for (const SDNode *User : N->uses()) {
- auto name = User->getOperationName(CurDAG);
if (!User->isMachineOpcode() ||
User->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
return false;
@@ -4274,25 +4273,24 @@ bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
if (!ShiftAmount || ShiftAmount->getZExtValue() > OpSize - TruncateSize)
return false;
- // Only make the replacement when it avoids clobbering used flags. This is a
- // similar heuristic as used in the conversion to LEA, namely looking at the
- // operand for an instruction that creates flags where those flags are used.
- // This will have both false positives and false negatives. Ideally, both of
- // these happen later on. Perhaps in copy to flags lowering or in register
- // allocation.
- bool MightClobberFlags = false;
+ // If the shift argument has non-dead EFLAGS, then this shift probably
+ // clobbers those flags making the transformation to RORX useful. This may
+ // have false negatives or positives so ideally this transformation is made
+ // later on.
+ bool ArgProducesFlags = false;
SDNode *Input = N->getOperand(0).getNode();
for (auto Use : Input->uses()) {
if (Use->getOpcode() == ISD::CopyToReg) {
auto *RegisterNode =
dyn_cast<RegisterSDNode>(Use->getOperand(1).getNode());
if (RegisterNode && RegisterNode->getReg() == X86::EFLAGS) {
- MightClobberFlags = true;
+ ArgProducesFlags = true;
break;
}
}
}
- if (!MightClobberFlags)
+ // Don't transform if the argument to this shift has dead EFLAGS.
+ if (!ArgProducesFlags)
return false;
// Make the replacement.
@@ -5327,7 +5325,7 @@ void X86DAGToDAGISel::Select(SDNode *Node) {
return;
[[fallthrough]];
case ISD::SRA:
- if (rightShiftUncloberFlags(Node))
+ if (rightShiftUnclobberFlags(Node))
return;
[[fallthrough]];
case ISD::SHL:
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