[llvm] [AArch64] Allow peephole to optimize AND + signed compare with 0 (PR #153608)

via llvm-commits llvm-commits at lists.llvm.org
Sat Nov 8 11:32:03 PST 2025


https://github.com/AZero13 updated https://github.com/llvm/llvm-project/pull/153608

>From 2b48dfd352e118adc9f43ee5e7c0911bf847a219 Mon Sep 17 00:00:00 2001
From: AZero13 <gfunni234 at gmail.com>
Date: Wed, 13 Aug 2025 19:37:23 -0400
Subject: [PATCH 1/2] Pre-commit test (NFC)

---
 .../AArch64/arm64-regress-opt-cmp-signed.mir  |  56 +++
 llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll | 344 ++++++++++++++++++
 2 files changed, 400 insertions(+)
 create mode 100644 llvm/test/CodeGen/AArch64/arm64-regress-opt-cmp-signed.mir

diff --git a/llvm/test/CodeGen/AArch64/arm64-regress-opt-cmp-signed.mir b/llvm/test/CodeGen/AArch64/arm64-regress-opt-cmp-signed.mir
new file mode 100644
index 0000000000000..777b65f24a057
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/arm64-regress-opt-cmp-signed.mir
@@ -0,0 +1,56 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=aarch64-linux-gnu -run-pass peephole-opt -o - %s | FileCheck %s
+--- |
+  define i32 @test01() nounwind {
+  entry:
+    %0 = select i1 true, i32 1, i32 0
+    %1 = and i32 %0, 65535
+    %2 = icmp sgt i32 %1, 0
+    br i1 %2, label %if.then, label %if.end
+
+  if.then:                                      ; preds = %entry
+    ret i32 1
+
+  if.end:                                       ; preds = %entry
+    ret i32 0
+  }
+...
+---
+name:            test01
+registers:
+  - { id: 0, class: gpr32 }
+  - { id: 1, class: gpr32common }
+body:             |
+  ; CHECK-LABEL: name: test01
+  ; CHECK: bb.0.entry:
+  ; CHECK-NEXT:   successors: %bb.2(0x40000000), %bb.1(0x40000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[MOVi32imm:%[0-9]+]]:gpr32 = MOVi32imm 1
+  ; CHECK-NEXT:   [[ANDWri:%[0-9]+]]:gpr32common = ANDWri killed [[ANDWri]], 15
+  ; CHECK-NEXT:   $wzr = SUBSWri killed [[ANDWri]], 0, 0, implicit-def $nzcv
+  ; CHECK-NEXT:   Bcc 12, %bb.2, implicit $nzcv
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.1.if.then:
+  ; CHECK-NEXT:   $w0 = MOVi32imm 1
+  ; CHECK-NEXT:   RET_ReallyLR implicit $w0
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.2.if.end:
+  ; CHECK-NEXT:   $w0 = MOVi32imm 0
+  ; CHECK-NEXT:   RET_ReallyLR implicit $w0
+  bb.0.entry:
+    successors: %bb.2.if.end, %bb.1.if.then
+
+    %0 = MOVi32imm 1
+    %1 = ANDWri killed %1, 15
+    $wzr = SUBSWri killed %1, 0, 0, implicit-def $nzcv
+    Bcc 12, %bb.2.if.end, implicit $nzcv
+
+  bb.1.if.then:
+    $w0 = MOVi32imm 1
+    RET_ReallyLR implicit $w0
+
+  bb.2.if.end:
+    $w0 = MOVi32imm 0
+    RET_ReallyLR implicit $w0
+
+...
diff --git a/llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll b/llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll
index 33c5ba7987974..4f5431f66d9eb 100644
--- a/llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll
+++ b/llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll
@@ -161,6 +161,350 @@ define i1 @lt64_u16_and_23(i64 %0) {
   ret i1 %3
 }
 
+define i1 @test_disjoint(i1 %0, i32 %1, i32 %2) {
+; CHECK-LABEL: test_disjoint:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr w9, w2, #0x800000
+; CHECK-NEXT:    lsl w8, w8, w1
+; CHECK-NEXT:    and w8, w9, w8
+; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    cset w8, eq
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i32 %2, 8388608
+  %4 = shl nuw i32 1, %1
+  %5 = and i32 %3, %4
+  %6 = icmp eq i32 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint2(i1 %0, i32 %1, i32 %2) {
+; CHECK-LABEL: test_disjoint2:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr w9, w2, #0x800000
+; CHECK-NEXT:    lsl w8, w8, w1
+; CHECK-NEXT:    and w8, w9, w8
+; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    cset w8, gt
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i32 %2, 8388608
+  %4 = shl nuw i32 1, %1
+  %5 = and i32 %3, %4
+  %6 = icmp sgt i32 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint3(i1 %0, i32 %1, i32 %2) {
+; CHECK-LABEL: test_disjoint3:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr w9, w2, #0x800000
+; CHECK-NEXT:    lsl w8, w8, w1
+; CHECK-NEXT:    and w8, w9, w8
+; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    cset w8, mi
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i32 %2, 8388608
+  %4 = shl nuw i32 1, %1
+  %5 = and i32 %3, %4
+  %6 = icmp slt i32 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint4(i1 %0, i32 %1, i32 %2) {
+; CHECK-LABEL: test_disjoint4:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr w9, w2, #0x800000
+; CHECK-NEXT:    lsl w8, w8, w1
+; CHECK-NEXT:    and w8, w9, w8
+; CHECK-NEXT:    cmp w8, #1
+; CHECK-NEXT:    cset w8, lt
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i32 %2, 8388608
+  %4 = shl nuw i32 1, %1
+  %5 = and i32 %3, %4
+  %6 = icmp sle i32 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint_inverse_4(i1 %0, i32 %1, i32 %2) {
+; CHECK-LABEL: test_disjoint_inverse_4:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr w9, w2, #0x800000
+; CHECK-NEXT:    lsl w8, w8, w1
+; CHECK-NEXT:    bic w8, w9, w8
+; CHECK-NEXT:    cmp w8, #1
+; CHECK-NEXT:    cset w8, lt
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i32 %2, 8388608
+  %4 = shl nuw i32 1, %1
+  %not = xor i32 %4, -1
+  %5 = and i32 %3, %not
+  %6 = icmp sle i32 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint_inverse(i1 %0, i32 %1, i32 %2) {
+; CHECK-LABEL: test_disjoint_inverse:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr w9, w2, #0x800000
+; CHECK-NEXT:    lsl w8, w8, w1
+; CHECK-NEXT:    bic w8, w9, w8
+; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    cset w8, eq
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i32 %2, 8388608
+  %4 = shl nuw i32 1, %1
+  %not = xor i32 %4, -1
+  %5 = and i32 %3, %not
+  %6 = icmp eq i32 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint2_inverse(i1 %0, i32 %1, i32 %2) {
+; CHECK-LABEL: test_disjoint2_inverse:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr w9, w2, #0x800000
+; CHECK-NEXT:    lsl w8, w8, w1
+; CHECK-NEXT:    bic w8, w9, w8
+; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    cset w8, gt
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i32 %2, 8388608
+  %4 = shl nuw i32 1, %1
+  %not = xor i32 %4, -1
+  %5 = and i32 %3, %not
+  %6 = icmp sgt i32 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint3_inverse(i1 %0, i32 %1, i32 %2) {
+; CHECK-LABEL: test_disjoint3_inverse:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr w9, w2, #0x800000
+; CHECK-NEXT:    lsl w8, w8, w1
+; CHECK-NEXT:    bic w8, w9, w8
+; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    cset w8, mi
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i32 %2, 8388608
+  %4 = shl nuw i32 1, %1
+  %not = xor i32 %4, -1
+  %5 = and i32 %3, %not
+  %6 = icmp slt i32 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint_64(i1 %0, i64 %1, i64 %2) {
+; CHECK-LABEL: test_disjoint_64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr x9, x2, #0x80000000000000
+; CHECK-NEXT:    lsl x8, x8, x1
+; CHECK-NEXT:    and x8, x9, x8
+; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    cset w8, eq
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i64 %2, 36028797018963968
+  %4 = shl nuw i64 1, %1
+  %5 = and i64 %3, %4
+  %6 = icmp eq i64 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint2_64(i1 %0, i64 %1, i64 %2) {
+; CHECK-LABEL: test_disjoint2_64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr x9, x2, #0x80000000000000
+; CHECK-NEXT:    lsl x8, x8, x1
+; CHECK-NEXT:    and x8, x9, x8
+; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    cset w8, gt
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i64 %2, 36028797018963968
+  %4 = shl nuw i64 1, %1
+  %5 = and i64 %3, %4
+  %6 = icmp sgt i64 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint3_64(i1 %0, i64 %1, i64 %2) {
+; CHECK-LABEL: test_disjoint3_64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr x9, x2, #0x80000000000000
+; CHECK-NEXT:    lsl x8, x8, x1
+; CHECK-NEXT:    and x8, x9, x8
+; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    cset w8, mi
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i64 %2, 36028797018963968
+  %4 = shl nuw i64 1, %1
+  %5 = and i64 %3, %4
+  %6 = icmp slt i64 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint4_64(i1 %0, i64 %1, i64 %2) {
+; CHECK-LABEL: test_disjoint4_64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr x9, x2, #0x80000000000000
+; CHECK-NEXT:    lsl x8, x8, x1
+; CHECK-NEXT:    and x8, x9, x8
+; CHECK-NEXT:    cmp x8, #1
+; CHECK-NEXT:    cset w8, lt
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i64 %2, 36028797018963968
+  %4 = shl nuw i64 1, %1
+  %5 = and i64 %3, %4
+  %6 = icmp sle i64 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint_inverse_4_64(i1 %0, i64 %1, i64 %2) {
+; CHECK-LABEL: test_disjoint_inverse_4_64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr x9, x2, #0x80000000000000
+; CHECK-NEXT:    lsl x8, x8, x1
+; CHECK-NEXT:    bic x8, x9, x8
+; CHECK-NEXT:    cmp x8, #1
+; CHECK-NEXT:    cset w8, lt
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i64 %2, 36028797018963968
+  %4 = shl nuw i64 1, %1
+  %not = xor i64 %4, -1
+  %5 = and i64 %3, %not
+  %6 = icmp sle i64 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint_inverse_64(i1 %0, i64 %1, i64 %2) {
+; CHECK-LABEL: test_disjoint_inverse_64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr x9, x2, #0x80000000000000
+; CHECK-NEXT:    lsl x8, x8, x1
+; CHECK-NEXT:    bic x8, x9, x8
+; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    cset w8, eq
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i64 %2, 36028797018963968
+  %4 = shl nuw i64 1, %1
+  %not = xor i64 %4, -1
+  %5 = and i64 %3, %not
+  %6 = icmp eq i64 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint2_inverse_64(i1 %0, i64 %1, i64 %2) {
+; CHECK-LABEL: test_disjoint2_inverse_64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr x9, x2, #0x80000000000000
+; CHECK-NEXT:    lsl x8, x8, x1
+; CHECK-NEXT:    bic x8, x9, x8
+; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    cset w8, gt
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i64 %2, 36028797018963968
+  %4 = shl nuw i64 1, %1
+  %not = xor i64 %4, -1
+  %5 = and i64 %3, %not
+  %6 = icmp sgt i64 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
+define i1 @test_disjoint3_inverse_64(i1 %0, i64 %1, i64 %2) {
+; CHECK-LABEL: test_disjoint3_inverse_64:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w8, #1 // =0x1
+; CHECK-NEXT:    orr x9, x2, #0x80000000000000
+; CHECK-NEXT:    lsl x8, x8, x1
+; CHECK-NEXT:    bic x8, x9, x8
+; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    cset w8, mi
+; CHECK-NEXT:    orr w8, w0, w8
+; CHECK-NEXT:    and w0, w8, #0x1
+; CHECK-NEXT:    ret
+entry:
+  %3 = or disjoint i64 %2, 36028797018963968
+  %4 = shl nuw i64 1, %1
+  %not = xor i64 %4, -1
+  %5 = and i64 %3, %not
+  %6 = icmp slt i64 %5, 0
+  %7 = select i1 %0, i1 true, i1 %6
+  ret i1 %7
+}
+
 ; negative test
 define i1 @lt3_u8(i8 %0) {
 ; CHECK-LABEL: lt3_u8:

>From 8c1aff4c623b401a44fa72ff8365e9c19a916dfd Mon Sep 17 00:00:00 2001
From: AZero13 <gfunni234 at gmail.com>
Date: Fri, 22 Aug 2025 16:38:34 -0400
Subject: [PATCH 2/2] [AArch64] Allow peephole to optimize AND + signed compare
 with 0

This should be the peephole's job. Because and sets V flag to 0, this is why signed comparisons with 0 are okay to replace with tst. Note this is only for AArch64, because ANDS on ARM leaves the V flag the same.

Fixes: #154387
---
 llvm/lib/Target/AArch64/AArch64InstrInfo.cpp  | 48 ++++++++++++++++++-
 .../AArch64/arm64-regress-opt-cmp-signed.mir  |  3 +-
 llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll | 36 +++++---------
 3 files changed, 60 insertions(+), 27 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index 4b4073365483e..295ffa6bbe95f 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -1780,6 +1780,16 @@ static unsigned sForm(MachineInstr &Instr) {
   case AArch64::SUBSWri:
   case AArch64::SUBSXrr:
   case AArch64::SUBSXri:
+  case AArch64::ANDSWri:
+  case AArch64::ANDSWrr:
+  case AArch64::ANDSWrs:
+  case AArch64::ANDSXri:
+  case AArch64::ANDSXrr:
+  case AArch64::ANDSXrs:
+  case AArch64::BICSWrr:
+  case AArch64::BICSXrr:
+  case AArch64::BICSWrs:
+  case AArch64::BICSXrs:
     return Instr.getOpcode();
 
   case AArch64::ADDWrr:
@@ -1810,6 +1820,22 @@ static unsigned sForm(MachineInstr &Instr) {
     return AArch64::ANDSWri;
   case AArch64::ANDXri:
     return AArch64::ANDSXri;
+  case AArch64::ANDWrr:
+    return AArch64::ANDSWrr;
+  case AArch64::ANDWrs:
+    return AArch64::ANDSWrs;
+  case AArch64::ANDXrr:
+    return AArch64::ANDSXrr;
+  case AArch64::ANDXrs:
+    return AArch64::ANDSXrs;
+  case AArch64::BICWrr:
+    return AArch64::BICSWrr;
+  case AArch64::BICXrr:
+    return AArch64::BICSXrr;
+  case AArch64::BICWrs:
+    return AArch64::BICSWrs;
+  case AArch64::BICXrs:
+    return AArch64::BICSXrs;
   }
 }
 
@@ -1947,6 +1973,25 @@ static bool isSUBSRegImm(unsigned Opcode) {
   return Opcode == AArch64::SUBSWri || Opcode == AArch64::SUBSXri;
 }
 
+static bool isANDOpcode(MachineInstr &MI) {
+  unsigned Opc = sForm(MI);
+  switch (Opc) {
+  case AArch64::ANDSWri:
+  case AArch64::ANDSWrr:
+  case AArch64::ANDSWrs:
+  case AArch64::ANDSXri:
+  case AArch64::ANDSXrr:
+  case AArch64::ANDSXrs:
+  case AArch64::BICSWrr:
+  case AArch64::BICSXrr:
+  case AArch64::BICSWrs:
+  case AArch64::BICSXrs:
+    return true;
+  default:
+    return false;
+  }
+}
+
 /// Check if CmpInstr can be substituted by MI.
 ///
 /// CmpInstr can be substituted:
@@ -1984,7 +2029,8 @@ static bool canInstrSubstituteCmpInstr(MachineInstr &MI, MachineInstr &CmpInstr,
   // 1) MI and CmpInstr set N and V to the same value.
   // 2) If MI is add/sub with no-signed-wrap, it produces a poison value when
   //    signed overflow occurs, so CmpInstr could still be simplified away.
-  if (NZVCUsed->V && !MI.getFlag(MachineInstr::NoSWrap))
+  // Note that Ands and Bics instructions always clear the V flag.
+  if (NZVCUsed->V && !MI.getFlag(MachineInstr::NoSWrap) && !isANDOpcode(MI))
     return false;
 
   AccessKind AccessToCheck = AK_Write;
diff --git a/llvm/test/CodeGen/AArch64/arm64-regress-opt-cmp-signed.mir b/llvm/test/CodeGen/AArch64/arm64-regress-opt-cmp-signed.mir
index 777b65f24a057..8c31e7c2d1cec 100644
--- a/llvm/test/CodeGen/AArch64/arm64-regress-opt-cmp-signed.mir
+++ b/llvm/test/CodeGen/AArch64/arm64-regress-opt-cmp-signed.mir
@@ -26,8 +26,7 @@ body:             |
   ; CHECK-NEXT:   successors: %bb.2(0x40000000), %bb.1(0x40000000)
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT:   [[MOVi32imm:%[0-9]+]]:gpr32 = MOVi32imm 1
-  ; CHECK-NEXT:   [[ANDWri:%[0-9]+]]:gpr32common = ANDWri killed [[ANDWri]], 15
-  ; CHECK-NEXT:   $wzr = SUBSWri killed [[ANDWri]], 0, 0, implicit-def $nzcv
+  ; CHECK-NEXT:   [[ANDSWri:%[0-9]+]]:gpr32common = ANDSWri killed [[ANDSWri]], 15, implicit-def $nzcv
   ; CHECK-NEXT:   Bcc 12, %bb.2, implicit $nzcv
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT: bb.1.if.then:
diff --git a/llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll b/llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll
index 4f5431f66d9eb..8297fa2d4e3f9 100644
--- a/llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll
+++ b/llvm/test/CodeGen/AArch64/icmp-ult-eq-fold.ll
@@ -167,8 +167,7 @@ define i1 @test_disjoint(i1 %0, i32 %1, i32 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr w9, w2, #0x800000
 ; CHECK-NEXT:    lsl w8, w8, w1
-; CHECK-NEXT:    and w8, w9, w8
-; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    tst w9, w8
 ; CHECK-NEXT:    cset w8, eq
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -188,8 +187,7 @@ define i1 @test_disjoint2(i1 %0, i32 %1, i32 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr w9, w2, #0x800000
 ; CHECK-NEXT:    lsl w8, w8, w1
-; CHECK-NEXT:    and w8, w9, w8
-; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    tst w9, w8
 ; CHECK-NEXT:    cset w8, gt
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -209,8 +207,7 @@ define i1 @test_disjoint3(i1 %0, i32 %1, i32 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr w9, w2, #0x800000
 ; CHECK-NEXT:    lsl w8, w8, w1
-; CHECK-NEXT:    and w8, w9, w8
-; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    tst w9, w8
 ; CHECK-NEXT:    cset w8, mi
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -273,8 +270,7 @@ define i1 @test_disjoint_inverse(i1 %0, i32 %1, i32 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr w9, w2, #0x800000
 ; CHECK-NEXT:    lsl w8, w8, w1
-; CHECK-NEXT:    bic w8, w9, w8
-; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    bics wzr, w9, w8
 ; CHECK-NEXT:    cset w8, eq
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -295,8 +291,7 @@ define i1 @test_disjoint2_inverse(i1 %0, i32 %1, i32 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr w9, w2, #0x800000
 ; CHECK-NEXT:    lsl w8, w8, w1
-; CHECK-NEXT:    bic w8, w9, w8
-; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    bics wzr, w9, w8
 ; CHECK-NEXT:    cset w8, gt
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -317,8 +312,7 @@ define i1 @test_disjoint3_inverse(i1 %0, i32 %1, i32 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr w9, w2, #0x800000
 ; CHECK-NEXT:    lsl w8, w8, w1
-; CHECK-NEXT:    bic w8, w9, w8
-; CHECK-NEXT:    cmp w8, #0
+; CHECK-NEXT:    bics wzr, w9, w8
 ; CHECK-NEXT:    cset w8, mi
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -339,8 +333,7 @@ define i1 @test_disjoint_64(i1 %0, i64 %1, i64 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr x9, x2, #0x80000000000000
 ; CHECK-NEXT:    lsl x8, x8, x1
-; CHECK-NEXT:    and x8, x9, x8
-; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    tst x9, x8
 ; CHECK-NEXT:    cset w8, eq
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -360,8 +353,7 @@ define i1 @test_disjoint2_64(i1 %0, i64 %1, i64 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr x9, x2, #0x80000000000000
 ; CHECK-NEXT:    lsl x8, x8, x1
-; CHECK-NEXT:    and x8, x9, x8
-; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    tst x9, x8
 ; CHECK-NEXT:    cset w8, gt
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -381,8 +373,7 @@ define i1 @test_disjoint3_64(i1 %0, i64 %1, i64 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr x9, x2, #0x80000000000000
 ; CHECK-NEXT:    lsl x8, x8, x1
-; CHECK-NEXT:    and x8, x9, x8
-; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    tst x9, x8
 ; CHECK-NEXT:    cset w8, mi
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -445,8 +436,7 @@ define i1 @test_disjoint_inverse_64(i1 %0, i64 %1, i64 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr x9, x2, #0x80000000000000
 ; CHECK-NEXT:    lsl x8, x8, x1
-; CHECK-NEXT:    bic x8, x9, x8
-; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    bics xzr, x9, x8
 ; CHECK-NEXT:    cset w8, eq
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -467,8 +457,7 @@ define i1 @test_disjoint2_inverse_64(i1 %0, i64 %1, i64 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr x9, x2, #0x80000000000000
 ; CHECK-NEXT:    lsl x8, x8, x1
-; CHECK-NEXT:    bic x8, x9, x8
-; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    bics xzr, x9, x8
 ; CHECK-NEXT:    cset w8, gt
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1
@@ -489,8 +478,7 @@ define i1 @test_disjoint3_inverse_64(i1 %0, i64 %1, i64 %2) {
 ; CHECK-NEXT:    mov w8, #1 // =0x1
 ; CHECK-NEXT:    orr x9, x2, #0x80000000000000
 ; CHECK-NEXT:    lsl x8, x8, x1
-; CHECK-NEXT:    bic x8, x9, x8
-; CHECK-NEXT:    cmp x8, #0
+; CHECK-NEXT:    bics xzr, x9, x8
 ; CHECK-NEXT:    cset w8, mi
 ; CHECK-NEXT:    orr w8, w0, w8
 ; CHECK-NEXT:    and w0, w8, #0x1



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