9a091de7fe
Enable FoldImmediate for X86 by implementing X86InstrInfo::FoldImmediate. Also enhanced peephole by deleting identical instructions after FoldImmediate. Differential Revision: https://reviews.llvm.org/D151848
58 lines
2.0 KiB
LLVM
58 lines
2.0 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 3
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; RUN: llc < %s -mtriple=x86_64-unknown | FileCheck %s
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; When optimize for size, the constant $858993459 is moved into a register,
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; and use that register in following two andl instructions.
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define i32 @cnt32_optsize(i32 %x) nounwind readnone optsize {
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; CHECK-LABEL: cnt32_optsize:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: shrl %eax
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; CHECK-NEXT: andl $1431655765, %eax # imm = 0x55555555
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; CHECK-NEXT: subl %eax, %edi
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; CHECK-NEXT: movl $858993459, %eax # imm = 0x33333333
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; CHECK-NEXT: movl %edi, %ecx
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; CHECK-NEXT: andl %eax, %ecx
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; CHECK-NEXT: shrl $2, %edi
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; CHECK-NEXT: andl %eax, %edi
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; CHECK-NEXT: addl %ecx, %edi
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: shrl $4, %eax
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; CHECK-NEXT: addl %edi, %eax
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; CHECK-NEXT: andl $252645135, %eax # imm = 0xF0F0F0F
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; CHECK-NEXT: imull $16843009, %eax, %eax # imm = 0x1010101
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; CHECK-NEXT: shrl $24, %eax
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; CHECK-NEXT: retq
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%cnt = tail call i32 @llvm.ctpop.i32(i32 %x)
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ret i32 %cnt
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}
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; When optimize for speed, the constant $858993459 can be directly folded into
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; two andl instructions.
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define i32 @cnt32_optspeed(i32 %x) nounwind readnone {
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; CHECK-LABEL: cnt32_optspeed:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: shrl %eax
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; CHECK-NEXT: andl $1431655765, %eax # imm = 0x55555555
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; CHECK-NEXT: subl %eax, %edi
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: andl $858993459, %eax # imm = 0x33333333
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; CHECK-NEXT: shrl $2, %edi
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; CHECK-NEXT: andl $858993459, %edi # imm = 0x33333333
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; CHECK-NEXT: addl %eax, %edi
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: shrl $4, %eax
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; CHECK-NEXT: addl %edi, %eax
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; CHECK-NEXT: andl $252645135, %eax # imm = 0xF0F0F0F
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; CHECK-NEXT: imull $16843009, %eax, %eax # imm = 0x1010101
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; CHECK-NEXT: shrl $24, %eax
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; CHECK-NEXT: retq
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%cnt = tail call i32 @llvm.ctpop.i32(i32 %x)
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ret i32 %cnt
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}
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declare i32 @llvm.ctpop.i32(i32) nounwind readnone
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