[llvm] 5d2ece1 - [X86] Allow znver3/4/5 targets to use double-shift instructions by default (#132720)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 25 02:48:55 PDT 2025
Author: Simon Pilgrim
Date: 2025-06-25T10:48:51+01:00
New Revision: 5d2ece14378ef00b569e5f29034a0236d735da44
URL: https://github.com/llvm/llvm-project/commit/5d2ece14378ef00b569e5f29034a0236d735da44
DIFF: https://github.com/llvm/llvm-project/commit/5d2ece14378ef00b569e5f29034a0236d735da44.diff
LOG: [X86] Allow znver3/4/5 targets to use double-shift instructions by default (#132720)
While still not as fast as Intel targets, recent AMD znver3 + later CPUs
are not as microcoded+bottlenecked as previous AMD targets (now only
~2cy rthroughput) which improves on the expanded 3*shift+not+or sequence
we expand to as an alternative.
Noticed while triaging #132601
Added:
Modified:
llvm/lib/Target/X86/X86.td
llvm/test/CodeGen/X86/shift-i512.ll
llvm/test/CodeGen/X86/x86-64-double-shifts-var.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/X86/X86.td b/llvm/lib/Target/X86/X86.td
index bcda188d4c2cb..772e48efb8607 100644
--- a/llvm/lib/Target/X86/X86.td
+++ b/llvm/lib/Target/X86/X86.td
@@ -1574,7 +1574,7 @@ def ProcessorFeatures {
FeatureVPCLMULQDQ];
list<SubtargetFeature> ZN3AdditionalTuning = [TuningMacroFusion];
list<SubtargetFeature> ZN3Tuning =
- !listconcat(ZN2Tuning, ZN3AdditionalTuning);
+ !listremove(!listconcat(ZN2Tuning, ZN3AdditionalTuning), [TuningSlowSHLD]);
list<SubtargetFeature> ZN3Features =
!listconcat(ZN2Features, ZN3AdditionalFeatures);
diff --git a/llvm/test/CodeGen/X86/shift-i512.ll b/llvm/test/CodeGen/X86/shift-i512.ll
index c7da04171e6a1..756019d0e98a0 100644
--- a/llvm/test/CodeGen/X86/shift-i512.ll
+++ b/llvm/test/CodeGen/X86/shift-i512.ll
@@ -48,46 +48,20 @@ define <8 x i64> @shl_i512_1(<8 x i64> %a) {
;
; ZNVER4-LABEL: shl_i512_1:
; ZNVER4: # %bb.0:
-; ZNVER4-NEXT: vextracti32x4 $3, %zmm0, %xmm1
-; ZNVER4-NEXT: vmovq %xmm0, %rdx
-; ZNVER4-NEXT: vpextrq $1, %xmm0, %r9
-; ZNVER4-NEXT: vpextrq $1, %xmm1, %rax
-; ZNVER4-NEXT: vmovq %xmm1, %rcx
; ZNVER4-NEXT: vextracti32x4 $2, %zmm0, %xmm1
-; ZNVER4-NEXT: shrq $63, %rdx
-; ZNVER4-NEXT: vpextrq $1, %xmm1, %rsi
-; ZNVER4-NEXT: vmovq %xmm1, %rdi
-; ZNVER4-NEXT: vextracti128 $1, %ymm0, %xmm1
-; ZNVER4-NEXT: leaq (%rdx,%r9,2), %rdx
-; ZNVER4-NEXT: shrq $63, %r9
-; ZNVER4-NEXT: vpsllq $1, %xmm0, %xmm0
-; ZNVER4-NEXT: vmovq %xmm1, %r10
-; ZNVER4-NEXT: vpextrq $1, %xmm1, %r8
-; ZNVER4-NEXT: leaq (%r9,%r10,2), %r9
-; ZNVER4-NEXT: shrq $63, %r10
-; ZNVER4-NEXT: vmovq %rdx, %xmm4
-; ZNVER4-NEXT: leaq (%r10,%r8,2), %r10
-; ZNVER4-NEXT: shrq $63, %r8
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm4[0]
-; ZNVER4-NEXT: leaq (%r8,%rdi,2), %r8
-; ZNVER4-NEXT: shrq $63, %rdi
-; ZNVER4-NEXT: leaq (%rdi,%rsi,2), %rdi
-; ZNVER4-NEXT: shrq $63, %rsi
-; ZNVER4-NEXT: leaq (%rsi,%rcx,2), %rsi
-; ZNVER4-NEXT: shrq $63, %rcx
-; ZNVER4-NEXT: vmovq %r8, %xmm3
-; ZNVER4-NEXT: leaq (%rcx,%rax,2), %rax
-; ZNVER4-NEXT: vmovq %rsi, %xmm2
-; ZNVER4-NEXT: vmovq %rax, %xmm1
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm1 = xmm2[0],xmm1[0]
-; ZNVER4-NEXT: vmovq %rdi, %xmm2
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm2 = xmm3[0],xmm2[0]
-; ZNVER4-NEXT: vmovq %r10, %xmm3
+; ZNVER4-NEXT: vextracti128 $1, %ymm0, %xmm2
+; ZNVER4-NEXT: vpshufd {{.*#+}} xmm3 = xmm0[2,3,2,3]
+; ZNVER4-NEXT: vpsllq $1, %xmm0, %xmm4
; ZNVER4-NEXT: vinserti128 $1, %xmm1, %ymm2, %ymm1
-; ZNVER4-NEXT: vmovq %r9, %xmm2
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm2 = xmm2[0],xmm3[0]
-; ZNVER4-NEXT: vinserti128 $1, %xmm2, %ymm0, %ymm0
-; ZNVER4-NEXT: vinserti64x4 $1, %ymm1, %zmm0, %zmm0
+; ZNVER4-NEXT: vpshldq $1, %xmm3, %xmm2, %xmm3
+; ZNVER4-NEXT: vextracti64x4 $1, %zmm0, %ymm2
+; ZNVER4-NEXT: vpshufd {{.*#+}} ymm1 = ymm1[2,3,2,3,6,7,6,7]
+; ZNVER4-NEXT: vpshldq $1, %ymm1, %ymm2, %ymm1
+; ZNVER4-NEXT: vinserti128 $1, %xmm3, %ymm4, %ymm3
+; ZNVER4-NEXT: vinserti64x4 $1, %ymm1, %zmm3, %zmm1
+; ZNVER4-NEXT: vpshufd {{.*#+}} zmm3 = zmm0[2,3,2,3,6,7,6,7,10,11,10,11,14,15,14,15]
+; ZNVER4-NEXT: vpshldq $1, %zmm0, %zmm3, %zmm0
+; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} zmm0 = zmm1[0],zmm0[0],zmm1[2],zmm0[2],zmm1[4],zmm0[4],zmm1[6],zmm0[6]
; ZNVER4-NEXT: retq
%d = bitcast <8 x i64> %a to i512
%s = shl i512 %d, 1
@@ -142,65 +116,21 @@ define <8 x i64> @lshr_i512_1(<8 x i64> %a) {
;
; ZNVER4-LABEL: lshr_i512_1:
; ZNVER4: # %bb.0:
-; ZNVER4-NEXT: pushq %rbx
-; ZNVER4-NEXT: .cfi_def_cfa_offset 16
-; ZNVER4-NEXT: .cfi_offset %rbx, -16
+; ZNVER4-NEXT: vextracti32x4 $2, %zmm0, %xmm3
; ZNVER4-NEXT: vextracti128 $1, %ymm0, %xmm1
-; ZNVER4-NEXT: vmovq %xmm0, %r10
-; ZNVER4-NEXT: vpextrq $1, %xmm0, %rsi
-; ZNVER4-NEXT: vpextrq $1, %xmm1, %rcx
-; ZNVER4-NEXT: vmovq %xmm1, %r9
-; ZNVER4-NEXT: vextracti32x4 $2, %zmm0, %xmm1
-; ZNVER4-NEXT: vextracti32x4 $3, %zmm0, %xmm0
-; ZNVER4-NEXT: shrq %r10
-; ZNVER4-NEXT: vpextrq $1, %xmm0, %rax
-; ZNVER4-NEXT: vmovq %xmm0, %rdx
-; ZNVER4-NEXT: vmovq %xmm1, %rdi
-; ZNVER4-NEXT: vpextrq $1, %xmm1, %r11
-; ZNVER4-NEXT: vpshufd {{.*#+}} xmm0 = xmm0[2,3,2,3]
-; ZNVER4-NEXT: movq %rdx, %r8
-; ZNVER4-NEXT: shrq %r8
-; ZNVER4-NEXT: shlq $63, %rax
-; ZNVER4-NEXT: movq %rdi, %rbx
-; ZNVER4-NEXT: shrq %rbx
-; ZNVER4-NEXT: shlq $63, %rdx
-; ZNVER4-NEXT: shlq $63, %rdi
-; ZNVER4-NEXT: vpsrlq $1, %xmm0, %xmm0
-; ZNVER4-NEXT: orq %r8, %rax
-; ZNVER4-NEXT: movq %r11, %r8
-; ZNVER4-NEXT: shlq $63, %r8
-; ZNVER4-NEXT: shrq %r11
-; ZNVER4-NEXT: orq %rbx, %r8
-; ZNVER4-NEXT: movq %r9, %rbx
-; ZNVER4-NEXT: orq %r11, %rdx
-; ZNVER4-NEXT: movq %rsi, %r11
-; ZNVER4-NEXT: shrq %r11
-; ZNVER4-NEXT: shlq $63, %rbx
-; ZNVER4-NEXT: shrq %r9
-; ZNVER4-NEXT: shlq $63, %rsi
-; ZNVER4-NEXT: vmovq %rax, %xmm4
-; ZNVER4-NEXT: orq %r11, %rbx
-; ZNVER4-NEXT: movq %rcx, %r11
-; ZNVER4-NEXT: shlq $63, %r11
-; ZNVER4-NEXT: shrq %rcx
-; ZNVER4-NEXT: orq %r10, %rsi
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm0 = xmm4[0],xmm0[0]
-; ZNVER4-NEXT: orq %r9, %r11
-; ZNVER4-NEXT: orq %rdi, %rcx
-; ZNVER4-NEXT: vmovq %rbx, %xmm3
-; ZNVER4-NEXT: vmovq %rcx, %xmm1
-; ZNVER4-NEXT: vmovq %r11, %xmm2
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm1 = xmm2[0],xmm1[0]
-; ZNVER4-NEXT: vmovq %rsi, %xmm2
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm2 = xmm2[0],xmm3[0]
-; ZNVER4-NEXT: vmovq %r8, %xmm3
-; ZNVER4-NEXT: vinserti128 $1, %xmm1, %ymm2, %ymm1
-; ZNVER4-NEXT: vmovq %rdx, %xmm2
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm2 = xmm3[0],xmm2[0]
-; ZNVER4-NEXT: vinserti128 $1, %xmm0, %ymm2, %ymm0
-; ZNVER4-NEXT: vinserti64x4 $1, %ymm0, %zmm1, %zmm0
-; ZNVER4-NEXT: popq %rbx
-; ZNVER4-NEXT: .cfi_def_cfa_offset 8
+; ZNVER4-NEXT: vextracti32x4 $3, %zmm0, %xmm2
+; ZNVER4-NEXT: vpshufd {{.*#+}} xmm4 = xmm3[2,3,2,3]
+; ZNVER4-NEXT: vinserti128 $1, %xmm3, %ymm1, %ymm1
+; ZNVER4-NEXT: vpshufd {{.*#+}} ymm3 = ymm0[2,3,2,3,6,7,6,7]
+; ZNVER4-NEXT: vpshldq $63, %xmm4, %xmm2, %xmm4
+; ZNVER4-NEXT: vpshufd {{.*#+}} xmm2 = xmm2[2,3,2,3]
+; ZNVER4-NEXT: vpshldq $63, %ymm3, %ymm1, %ymm1
+; ZNVER4-NEXT: vpshufd {{.*#+}} zmm3 = zmm0[2,3,2,3,6,7,6,7,10,11,10,11,14,15,14,15]
+; ZNVER4-NEXT: vpsrlq $1, %xmm2, %xmm2
+; ZNVER4-NEXT: vpshldq $63, %zmm0, %zmm3, %zmm0
+; ZNVER4-NEXT: vinserti128 $1, %xmm2, %ymm4, %ymm2
+; ZNVER4-NEXT: vinserti64x4 $1, %ymm2, %zmm1, %zmm1
+; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} zmm0 = zmm0[0],zmm1[0],zmm0[2],zmm1[2],zmm0[4],zmm1[4],zmm0[6],zmm1[6]
; ZNVER4-NEXT: retq
%d = bitcast <8 x i64> %a to i512
%s = lshr i512 %d, 1
@@ -255,65 +185,21 @@ define <8 x i64> @ashr_i512_1(<8 x i64> %a) {
;
; ZNVER4-LABEL: ashr_i512_1:
; ZNVER4: # %bb.0:
-; ZNVER4-NEXT: pushq %rbx
-; ZNVER4-NEXT: .cfi_def_cfa_offset 16
-; ZNVER4-NEXT: .cfi_offset %rbx, -16
+; ZNVER4-NEXT: vextracti32x4 $2, %zmm0, %xmm3
; ZNVER4-NEXT: vextracti128 $1, %ymm0, %xmm1
-; ZNVER4-NEXT: vmovq %xmm0, %r10
-; ZNVER4-NEXT: vpextrq $1, %xmm0, %rsi
-; ZNVER4-NEXT: vpextrq $1, %xmm1, %rcx
-; ZNVER4-NEXT: vmovq %xmm1, %r9
-; ZNVER4-NEXT: vextracti32x4 $2, %zmm0, %xmm1
-; ZNVER4-NEXT: vextracti32x4 $3, %zmm0, %xmm0
-; ZNVER4-NEXT: shrq %r10
-; ZNVER4-NEXT: vpextrq $1, %xmm0, %rax
-; ZNVER4-NEXT: vmovq %xmm0, %rdx
-; ZNVER4-NEXT: vmovq %xmm1, %rdi
-; ZNVER4-NEXT: vpextrq $1, %xmm1, %r11
-; ZNVER4-NEXT: vpshufd {{.*#+}} xmm0 = xmm0[2,3,2,3]
-; ZNVER4-NEXT: movq %rdx, %r8
-; ZNVER4-NEXT: shrq %r8
-; ZNVER4-NEXT: shlq $63, %rax
-; ZNVER4-NEXT: movq %rdi, %rbx
-; ZNVER4-NEXT: shrq %rbx
-; ZNVER4-NEXT: shlq $63, %rdx
-; ZNVER4-NEXT: shlq $63, %rdi
-; ZNVER4-NEXT: vpsraq $1, %xmm0, %xmm0
-; ZNVER4-NEXT: orq %r8, %rax
-; ZNVER4-NEXT: movq %r11, %r8
-; ZNVER4-NEXT: shlq $63, %r8
-; ZNVER4-NEXT: shrq %r11
-; ZNVER4-NEXT: orq %rbx, %r8
-; ZNVER4-NEXT: movq %r9, %rbx
-; ZNVER4-NEXT: orq %r11, %rdx
-; ZNVER4-NEXT: movq %rsi, %r11
-; ZNVER4-NEXT: shrq %r11
-; ZNVER4-NEXT: shlq $63, %rbx
-; ZNVER4-NEXT: shrq %r9
-; ZNVER4-NEXT: shlq $63, %rsi
-; ZNVER4-NEXT: vmovq %rax, %xmm4
-; ZNVER4-NEXT: orq %r11, %rbx
-; ZNVER4-NEXT: movq %rcx, %r11
-; ZNVER4-NEXT: shlq $63, %r11
-; ZNVER4-NEXT: shrq %rcx
-; ZNVER4-NEXT: orq %r10, %rsi
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm0 = xmm4[0],xmm0[0]
-; ZNVER4-NEXT: orq %r9, %r11
-; ZNVER4-NEXT: orq %rdi, %rcx
-; ZNVER4-NEXT: vmovq %rbx, %xmm3
-; ZNVER4-NEXT: vmovq %rcx, %xmm1
-; ZNVER4-NEXT: vmovq %r11, %xmm2
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm1 = xmm2[0],xmm1[0]
-; ZNVER4-NEXT: vmovq %rsi, %xmm2
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm2 = xmm2[0],xmm3[0]
-; ZNVER4-NEXT: vmovq %r8, %xmm3
-; ZNVER4-NEXT: vinserti128 $1, %xmm1, %ymm2, %ymm1
-; ZNVER4-NEXT: vmovq %rdx, %xmm2
-; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} xmm2 = xmm3[0],xmm2[0]
-; ZNVER4-NEXT: vinserti128 $1, %xmm0, %ymm2, %ymm0
-; ZNVER4-NEXT: vinserti64x4 $1, %ymm0, %zmm1, %zmm0
-; ZNVER4-NEXT: popq %rbx
-; ZNVER4-NEXT: .cfi_def_cfa_offset 8
+; ZNVER4-NEXT: vextracti32x4 $3, %zmm0, %xmm2
+; ZNVER4-NEXT: vpshufd {{.*#+}} xmm4 = xmm3[2,3,2,3]
+; ZNVER4-NEXT: vinserti128 $1, %xmm3, %ymm1, %ymm1
+; ZNVER4-NEXT: vpshufd {{.*#+}} ymm3 = ymm0[2,3,2,3,6,7,6,7]
+; ZNVER4-NEXT: vpshldq $63, %xmm4, %xmm2, %xmm4
+; ZNVER4-NEXT: vpshufd {{.*#+}} xmm2 = xmm2[2,3,2,3]
+; ZNVER4-NEXT: vpshldq $63, %ymm3, %ymm1, %ymm1
+; ZNVER4-NEXT: vpshufd {{.*#+}} zmm3 = zmm0[2,3,2,3,6,7,6,7,10,11,10,11,14,15,14,15]
+; ZNVER4-NEXT: vpsraq $1, %xmm2, %xmm2
+; ZNVER4-NEXT: vpshldq $63, %zmm0, %zmm3, %zmm0
+; ZNVER4-NEXT: vinserti128 $1, %xmm2, %ymm4, %ymm2
+; ZNVER4-NEXT: vinserti64x4 $1, %ymm2, %zmm1, %zmm1
+; ZNVER4-NEXT: vpunpcklqdq {{.*#+}} zmm0 = zmm0[0],zmm1[0],zmm0[2],zmm1[2],zmm0[4],zmm1[4],zmm0[6],zmm1[6]
; ZNVER4-NEXT: retq
%d = bitcast <8 x i64> %a to i512
%s = ashr i512 %d, 1
diff --git a/llvm/test/CodeGen/X86/x86-64-double-shifts-var.ll b/llvm/test/CodeGen/X86/x86-64-double-shifts-var.ll
index 58f6a66aeff79..c5e879c0135f4 100644
--- a/llvm/test/CodeGen/X86/x86-64-double-shifts-var.ll
+++ b/llvm/test/CodeGen/X86/x86-64-double-shifts-var.ll
@@ -12,12 +12,12 @@
; RUN: llc < %s -mtriple=x86_64-- -mcpu=bdver1 | FileCheck %s --check-prefixes=BMI
; RUN: llc < %s -mtriple=x86_64-- -mcpu=bdver2 | FileCheck %s --check-prefixes=BMI
; RUN: llc < %s -mtriple=x86_64-- -mcpu=bdver3 | FileCheck %s --check-prefixes=BMI
-; RUN: llc < %s -mtriple=x86_64-- -mcpu=bdver4 | FileCheck %s --check-prefixes=BMI2
-; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver1 | FileCheck %s --check-prefixes=BMI2
-; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver2 | FileCheck %s --check-prefixes=BMI2
-; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver3 | FileCheck %s --check-prefixes=BMI2
-; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver4 | FileCheck %s --check-prefixes=BMI2
-; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver5 | FileCheck %s --check-prefixes=BMI2
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=bdver4 | FileCheck %s --check-prefixes=BMI2-SLOW
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver1 | FileCheck %s --check-prefixes=BMI2-SLOW
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver2 | FileCheck %s --check-prefixes=BMI2-SLOW
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver3 | FileCheck %s --check-prefixes=BMI2-FAST
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver4 | FileCheck %s --check-prefixes=BMI2-FAST
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=znver5 | FileCheck %s --check-prefixes=BMI2-FAST
; Verify that for the X86_64 processors that are known to have poor latency
; double precision shift instructions we do not generate 'shld' or 'shrd'
@@ -53,15 +53,23 @@ define i64 @lshift(i64 %a, i64 %b, i32 %c) nounwind readnone {
; BMI-NEXT: orq %rdi, %rax
; BMI-NEXT: retq
;
-; BMI2-LABEL: lshift:
-; BMI2: # %bb.0: # %entry
-; BMI2-NEXT: # kill: def $edx killed $edx def $rdx
-; BMI2-NEXT: shlxq %rdx, %rdi, %rcx
-; BMI2-NEXT: notb %dl
-; BMI2-NEXT: shrq %rsi
-; BMI2-NEXT: shrxq %rdx, %rsi, %rax
-; BMI2-NEXT: orq %rcx, %rax
-; BMI2-NEXT: retq
+; BMI2-SLOW-LABEL: lshift:
+; BMI2-SLOW: # %bb.0: # %entry
+; BMI2-SLOW-NEXT: # kill: def $edx killed $edx def $rdx
+; BMI2-SLOW-NEXT: shlxq %rdx, %rdi, %rcx
+; BMI2-SLOW-NEXT: notb %dl
+; BMI2-SLOW-NEXT: shrq %rsi
+; BMI2-SLOW-NEXT: shrxq %rdx, %rsi, %rax
+; BMI2-SLOW-NEXT: orq %rcx, %rax
+; BMI2-SLOW-NEXT: retq
+;
+; BMI2-FAST-LABEL: lshift:
+; BMI2-FAST: # %bb.0: # %entry
+; BMI2-FAST-NEXT: movl %edx, %ecx
+; BMI2-FAST-NEXT: movq %rdi, %rax
+; BMI2-FAST-NEXT: # kill: def $cl killed $cl killed $ecx
+; BMI2-FAST-NEXT: shldq %cl, %rsi, %rax
+; BMI2-FAST-NEXT: retq
entry:
%sh_prom = zext i32 %c to i64
%shl = shl i64 %a, %sh_prom
@@ -100,15 +108,23 @@ define i64 @rshift(i64 %a, i64 %b, i32 %c) nounwind readnone {
; BMI-NEXT: orq %rdi, %rax
; BMI-NEXT: retq
;
-; BMI2-LABEL: rshift:
-; BMI2: # %bb.0: # %entry
-; BMI2-NEXT: # kill: def $edx killed $edx def $rdx
-; BMI2-NEXT: shrxq %rdx, %rdi, %rcx
-; BMI2-NEXT: notb %dl
-; BMI2-NEXT: addq %rsi, %rsi
-; BMI2-NEXT: shlxq %rdx, %rsi, %rax
-; BMI2-NEXT: orq %rcx, %rax
-; BMI2-NEXT: retq
+; BMI2-SLOW-LABEL: rshift:
+; BMI2-SLOW: # %bb.0: # %entry
+; BMI2-SLOW-NEXT: # kill: def $edx killed $edx def $rdx
+; BMI2-SLOW-NEXT: shrxq %rdx, %rdi, %rcx
+; BMI2-SLOW-NEXT: notb %dl
+; BMI2-SLOW-NEXT: addq %rsi, %rsi
+; BMI2-SLOW-NEXT: shlxq %rdx, %rsi, %rax
+; BMI2-SLOW-NEXT: orq %rcx, %rax
+; BMI2-SLOW-NEXT: retq
+;
+; BMI2-FAST-LABEL: rshift:
+; BMI2-FAST: # %bb.0: # %entry
+; BMI2-FAST-NEXT: movl %edx, %ecx
+; BMI2-FAST-NEXT: movq %rdi, %rax
+; BMI2-FAST-NEXT: # kill: def $cl killed $cl killed $ecx
+; BMI2-FAST-NEXT: shrdq %cl, %rsi, %rax
+; BMI2-FAST-NEXT: retq
entry:
%sh_prom = zext i32 %c to i64
%shr = lshr i64 %a, %sh_prom
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