[llvm] a4a9803 - [X86] shouldFoldMaskToVariableShiftPair should be true for scalars up to the biggest legal type (#158068)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 8 18:04:00 PDT 2025
Author: AZero13
Date: 2025-10-09T09:03:56+08:00
New Revision: a4a98033c3deb6bc9a438f3cb9e0e1716da5bc00
URL: https://github.com/llvm/llvm-project/commit/a4a98033c3deb6bc9a438f3cb9e0e1716da5bc00
DIFF: https://github.com/llvm/llvm-project/commit/a4a98033c3deb6bc9a438f3cb9e0e1716da5bc00.diff
LOG: [X86] shouldFoldMaskToVariableShiftPair should be true for scalars up to the biggest legal type (#158068)
For X86, we want to do this for scalars up to the biggest legal type.
Having it be for types bigger results in bloated code.
Added:
llvm/test/CodeGen/X86/and-mask-variable.ll
Modified:
llvm/lib/Target/X86/X86ISelLowering.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 931a10b700c87..9580adebba712 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -3659,11 +3659,8 @@ bool X86TargetLowering::shouldFoldMaskToVariableShiftPair(SDValue Y) const {
if (VT.isVector())
return false;
- // 64-bit shifts on 32-bit targets produce really bad bloated code.
- if (VT == MVT::i64 && !Subtarget.is64Bit())
- return false;
-
- return true;
+ unsigned MaxWidth = Subtarget.is64Bit() ? 64 : 32;
+ return VT.getScalarSizeInBits() <= MaxWidth;
}
TargetLowering::ShiftLegalizationStrategy
diff --git a/llvm/test/CodeGen/X86/and-mask-variable.ll b/llvm/test/CodeGen/X86/and-mask-variable.ll
new file mode 100644
index 0000000000000..d89f0db6a0c5b
--- /dev/null
+++ b/llvm/test/CodeGen/X86/and-mask-variable.ll
@@ -0,0 +1,212 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=i686-unknown-linux-gnu -mattr=-bmi,-tbm,-bmi2,+fast-bextr < %s | FileCheck %s --check-prefixes=X86-NOBMI
+; RUN: llc -mtriple=i686-unknown-linux-gnu -mattr=+bmi,+tbm,+bmi2,+fast-bextr < %s | FileCheck %s --check-prefixes=X86-BMI2
+; RUN: llc -mtriple=i686-unknown-linux-gnu -mattr=+bmi,-tbm,+bmi2,+fast-bextr < %s | FileCheck %s --check-prefixes=X86-BMI2
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -mattr=-bmi,-tbm,-bmi2,+fast-bextr < %s | FileCheck %s --check-prefixes=X64-NOBMI
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -mattr=+bmi,+tbm,+bmi2,+fast-bextr < %s | FileCheck %s --check-prefixes=X64-BMI2
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -mattr=+bmi,-tbm,+bmi2,+fast-bextr < %s | FileCheck %s --check-prefixes=X64-BMI2
+
+define i32 @mask_pair(i32 %x, i32 %y) nounwind {
+; X86-NOBMI-LABEL: mask_pair:
+; X86-NOBMI: # %bb.0:
+; X86-NOBMI-NEXT: movzbl {{[0-9]+}}(%esp), %ecx
+; X86-NOBMI-NEXT: movl {{[0-9]+}}(%esp), %eax
+; X86-NOBMI-NEXT: shrl %cl, %eax
+; X86-NOBMI-NEXT: shll %cl, %eax
+; X86-NOBMI-NEXT: retl
+;
+; X86-BMI2-LABEL: mask_pair:
+; X86-BMI2: # %bb.0:
+; X86-BMI2-NEXT: movzbl {{[0-9]+}}(%esp), %eax
+; X86-BMI2-NEXT: shrxl %eax, {{[0-9]+}}(%esp), %ecx
+; X86-BMI2-NEXT: shlxl %eax, %ecx, %eax
+; X86-BMI2-NEXT: retl
+;
+; X64-NOBMI-LABEL: mask_pair:
+; X64-NOBMI: # %bb.0:
+; X64-NOBMI-NEXT: movl %esi, %ecx
+; X64-NOBMI-NEXT: movl %edi, %eax
+; X64-NOBMI-NEXT: shrl %cl, %eax
+; X64-NOBMI-NEXT: # kill: def $cl killed $cl killed $ecx
+; X64-NOBMI-NEXT: shll %cl, %eax
+; X64-NOBMI-NEXT: retq
+;
+; X64-BMI2-LABEL: mask_pair:
+; X64-BMI2: # %bb.0:
+; X64-BMI2-NEXT: shrxl %esi, %edi, %eax
+; X64-BMI2-NEXT: shlxl %esi, %eax, %eax
+; X64-BMI2-NEXT: retq
+ %shl = shl nsw i32 -1, %y
+ %and = and i32 %shl, %x
+ ret i32 %and
+}
+
+define i64 @mask_pair_64(i64 %x, i64 %y) nounwind {
+; X86-NOBMI-LABEL: mask_pair_64:
+; X86-NOBMI: # %bb.0:
+; X86-NOBMI-NEXT: movzbl {{[0-9]+}}(%esp), %ecx
+; X86-NOBMI-NEXT: movl $-1, %edx
+; X86-NOBMI-NEXT: movl $-1, %eax
+; X86-NOBMI-NEXT: shll %cl, %eax
+; X86-NOBMI-NEXT: testb $32, %cl
+; X86-NOBMI-NEXT: je .LBB1_2
+; X86-NOBMI-NEXT: # %bb.1:
+; X86-NOBMI-NEXT: movl %eax, %edx
+; X86-NOBMI-NEXT: xorl %eax, %eax
+; X86-NOBMI-NEXT: .LBB1_2:
+; X86-NOBMI-NEXT: andl {{[0-9]+}}(%esp), %eax
+; X86-NOBMI-NEXT: andl {{[0-9]+}}(%esp), %edx
+; X86-NOBMI-NEXT: retl
+;
+; X86-BMI2-LABEL: mask_pair_64:
+; X86-BMI2: # %bb.0:
+; X86-BMI2-NEXT: movzbl {{[0-9]+}}(%esp), %ecx
+; X86-BMI2-NEXT: movl $-1, %edx
+; X86-BMI2-NEXT: shlxl %ecx, %edx, %eax
+; X86-BMI2-NEXT: testb $32, %cl
+; X86-BMI2-NEXT: je .LBB1_2
+; X86-BMI2-NEXT: # %bb.1:
+; X86-BMI2-NEXT: movl %eax, %edx
+; X86-BMI2-NEXT: xorl %eax, %eax
+; X86-BMI2-NEXT: .LBB1_2:
+; X86-BMI2-NEXT: andl {{[0-9]+}}(%esp), %eax
+; X86-BMI2-NEXT: andl {{[0-9]+}}(%esp), %edx
+; X86-BMI2-NEXT: retl
+;
+; X64-NOBMI-LABEL: mask_pair_64:
+; X64-NOBMI: # %bb.0:
+; X64-NOBMI-NEXT: movq %rsi, %rcx
+; X64-NOBMI-NEXT: movq %rdi, %rax
+; X64-NOBMI-NEXT: shrq %cl, %rax
+; X64-NOBMI-NEXT: # kill: def $cl killed $cl killed $rcx
+; X64-NOBMI-NEXT: shlq %cl, %rax
+; X64-NOBMI-NEXT: retq
+;
+; X64-BMI2-LABEL: mask_pair_64:
+; X64-BMI2: # %bb.0:
+; X64-BMI2-NEXT: shrxq %rsi, %rdi, %rax
+; X64-BMI2-NEXT: shlxq %rsi, %rax, %rax
+; X64-BMI2-NEXT: retq
+ %shl = shl nsw i64 -1, %y
+ %and = and i64 %shl, %x
+ ret i64 %and
+}
+
+define i128 @mask_pair_128(i128 %x, i128 %y) nounwind {
+; X86-NOBMI-LABEL: mask_pair_128:
+; X86-NOBMI: # %bb.0:
+; X86-NOBMI-NEXT: pushl %ebx
+; X86-NOBMI-NEXT: pushl %edi
+; X86-NOBMI-NEXT: pushl %esi
+; X86-NOBMI-NEXT: subl $32, %esp
+; X86-NOBMI-NEXT: movl {{[0-9]+}}(%esp), %ecx
+; X86-NOBMI-NEXT: movl {{[0-9]+}}(%esp), %eax
+; X86-NOBMI-NEXT: movl $-1, {{[0-9]+}}(%esp)
+; X86-NOBMI-NEXT: movl $-1, {{[0-9]+}}(%esp)
+; X86-NOBMI-NEXT: movl $-1, {{[0-9]+}}(%esp)
+; X86-NOBMI-NEXT: movl $-1, {{[0-9]+}}(%esp)
+; X86-NOBMI-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NOBMI-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NOBMI-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NOBMI-NEXT: movl $0, (%esp)
+; X86-NOBMI-NEXT: movl %ecx, %edx
+; X86-NOBMI-NEXT: shrb $3, %dl
+; X86-NOBMI-NEXT: andb $12, %dl
+; X86-NOBMI-NEXT: negb %dl
+; X86-NOBMI-NEXT: movsbl %dl, %ebx
+; X86-NOBMI-NEXT: movl 24(%esp,%ebx), %edx
+; X86-NOBMI-NEXT: movl 28(%esp,%ebx), %esi
+; X86-NOBMI-NEXT: shldl %cl, %edx, %esi
+; X86-NOBMI-NEXT: movl 16(%esp,%ebx), %edi
+; X86-NOBMI-NEXT: movl 20(%esp,%ebx), %ebx
+; X86-NOBMI-NEXT: shldl %cl, %ebx, %edx
+; X86-NOBMI-NEXT: shldl %cl, %edi, %ebx
+; X86-NOBMI-NEXT: # kill: def $cl killed $cl killed $ecx
+; X86-NOBMI-NEXT: shll %cl, %edi
+; X86-NOBMI-NEXT: andl {{[0-9]+}}(%esp), %edx
+; X86-NOBMI-NEXT: andl {{[0-9]+}}(%esp), %esi
+; X86-NOBMI-NEXT: andl {{[0-9]+}}(%esp), %edi
+; X86-NOBMI-NEXT: andl {{[0-9]+}}(%esp), %ebx
+; X86-NOBMI-NEXT: movl %esi, 12(%eax)
+; X86-NOBMI-NEXT: movl %edx, 8(%eax)
+; X86-NOBMI-NEXT: movl %ebx, 4(%eax)
+; X86-NOBMI-NEXT: movl %edi, (%eax)
+; X86-NOBMI-NEXT: addl $32, %esp
+; X86-NOBMI-NEXT: popl %esi
+; X86-NOBMI-NEXT: popl %edi
+; X86-NOBMI-NEXT: popl %ebx
+; X86-NOBMI-NEXT: retl $4
+;
+; X86-BMI2-LABEL: mask_pair_128:
+; X86-BMI2: # %bb.0:
+; X86-BMI2-NEXT: pushl %ebx
+; X86-BMI2-NEXT: pushl %edi
+; X86-BMI2-NEXT: pushl %esi
+; X86-BMI2-NEXT: subl $32, %esp
+; X86-BMI2-NEXT: movl {{[0-9]+}}(%esp), %ecx
+; X86-BMI2-NEXT: movl {{[0-9]+}}(%esp), %eax
+; X86-BMI2-NEXT: movl $-1, {{[0-9]+}}(%esp)
+; X86-BMI2-NEXT: movl $-1, {{[0-9]+}}(%esp)
+; X86-BMI2-NEXT: movl $-1, {{[0-9]+}}(%esp)
+; X86-BMI2-NEXT: movl $-1, {{[0-9]+}}(%esp)
+; X86-BMI2-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-BMI2-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-BMI2-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-BMI2-NEXT: movl $0, (%esp)
+; X86-BMI2-NEXT: movl %ecx, %edx
+; X86-BMI2-NEXT: shrb $3, %dl
+; X86-BMI2-NEXT: andb $12, %dl
+; X86-BMI2-NEXT: negb %dl
+; X86-BMI2-NEXT: movsbl %dl, %edi
+; X86-BMI2-NEXT: movl 24(%esp,%edi), %edx
+; X86-BMI2-NEXT: movl 28(%esp,%edi), %esi
+; X86-BMI2-NEXT: shldl %cl, %edx, %esi
+; X86-BMI2-NEXT: movl 16(%esp,%edi), %ebx
+; X86-BMI2-NEXT: movl 20(%esp,%edi), %edi
+; X86-BMI2-NEXT: shldl %cl, %edi, %edx
+; X86-BMI2-NEXT: shldl %cl, %ebx, %edi
+; X86-BMI2-NEXT: shlxl %ecx, %ebx, %ecx
+; X86-BMI2-NEXT: andl {{[0-9]+}}(%esp), %edx
+; X86-BMI2-NEXT: andl {{[0-9]+}}(%esp), %esi
+; X86-BMI2-NEXT: andl {{[0-9]+}}(%esp), %ecx
+; X86-BMI2-NEXT: andl {{[0-9]+}}(%esp), %edi
+; X86-BMI2-NEXT: movl %esi, 12(%eax)
+; X86-BMI2-NEXT: movl %edx, 8(%eax)
+; X86-BMI2-NEXT: movl %edi, 4(%eax)
+; X86-BMI2-NEXT: movl %ecx, (%eax)
+; X86-BMI2-NEXT: addl $32, %esp
+; X86-BMI2-NEXT: popl %esi
+; X86-BMI2-NEXT: popl %edi
+; X86-BMI2-NEXT: popl %ebx
+; X86-BMI2-NEXT: retl $4
+;
+; X64-NOBMI-LABEL: mask_pair_128:
+; X64-NOBMI: # %bb.0:
+; X64-NOBMI-NEXT: movq %rdx, %rcx
+; X64-NOBMI-NEXT: movq $-1, %rdx
+; X64-NOBMI-NEXT: movq $-1, %r8
+; X64-NOBMI-NEXT: shlq %cl, %r8
+; X64-NOBMI-NEXT: xorl %eax, %eax
+; X64-NOBMI-NEXT: testb $64, %cl
+; X64-NOBMI-NEXT: cmovneq %r8, %rdx
+; X64-NOBMI-NEXT: cmoveq %r8, %rax
+; X64-NOBMI-NEXT: andq %rdi, %rax
+; X64-NOBMI-NEXT: andq %rsi, %rdx
+; X64-NOBMI-NEXT: retq
+;
+; X64-BMI2-LABEL: mask_pair_128:
+; X64-BMI2: # %bb.0:
+; X64-BMI2-NEXT: movq $-1, %rcx
+; X64-BMI2-NEXT: shlxq %rdx, %rcx, %r8
+; X64-BMI2-NEXT: xorl %eax, %eax
+; X64-BMI2-NEXT: testb $64, %dl
+; X64-BMI2-NEXT: cmovneq %r8, %rcx
+; X64-BMI2-NEXT: cmoveq %r8, %rax
+; X64-BMI2-NEXT: andq %rdi, %rax
+; X64-BMI2-NEXT: andq %rsi, %rcx
+; X64-BMI2-NEXT: movq %rcx, %rdx
+; X64-BMI2-NEXT: retq
+ %shl = shl nsw i128 -1, %y
+ %and = and i128 %shl, %x
+ ret i128 %and
+}
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