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[X86][InstCombine] Add basic simplification support for BEXTR/BEXTRI intrinsics. 

This patch adds simplification support for the BEXTR/BEXTRI intrinsics to match gcc. This only supports cases that fold to 0 or can be fully constant folded. Theoretically we could support converting to AND if the shift part is unused or to only a shift if the mask doesn't modify any bits after an equivalent shl. gcc doesn't do these transformations either.

I put this in InstCombine, but it could be done in InstSimplify. It would be the first target specific intrinsic in InstSimplify.

Differential Revision: https://reviews.llvm.org/D36063

llvm-svn: 309603
This commit is contained in:
Craig Topper 2017-07-31 18:52:13 +00:00
parent 1b4e9ae384
commit 8324003818
2 changed files with 229 additions and 0 deletions
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26
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
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@ -2248,6 +2248,32 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
}
break;
case Intrinsic::x86_bmi_bextr_32:
case Intrinsic::x86_bmi_bextr_64:
case Intrinsic::x86_tbm_bextri_u32:
case Intrinsic::x86_tbm_bextri_u64:
// If the RHS is a constant we can try some simplifications.
if (auto *C = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
uint64_t Shift = C->getZExtValue();
uint64_t Length = (Shift >> 8) & 0xff;
Shift &= 0xff;
unsigned BitWidth = II->getType()->getIntegerBitWidth();
// If the length is 0 or the shift is out of range, replace with zero.
if (Length == 0 || Shift >= BitWidth)
return replaceInstUsesWith(CI, ConstantInt::get(II->getType(), 0));
// If the LHS is also a constant, we can completely constant fold this.
if (auto *InC = dyn_cast<ConstantInt>(II->getArgOperand(0))) {
uint64_t Result = InC->getZExtValue() >> Shift;
if (Length > BitWidth)
Length = BitWidth;
Result &= maskTrailingOnes<uint64_t>(Length);
return replaceInstUsesWith(CI, ConstantInt::get(II->getType(), Result));
}
// TODO should we turn this into 'and' if shift is 0? Or 'shl' if we
// are only masking bits that a shift already cleared?
}
break;
case Intrinsic::x86_vcvtph2ps_128:
case Intrinsic::x86_vcvtph2ps_256: {
auto Arg = II->getArgOperand(0);

203
llvm/test/Transforms/InstCombine/X86/x86-bmi-tbm.ll Normal file
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@ -0,0 +1,203 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
declare i32 @llvm.x86.tbm.bextri.u32(i32, i32) nounwind readnone
declare i64 @llvm.x86.tbm.bextri.u64(i64, i64) nounwind readnone
declare i32 @llvm.x86.bmi.bextr.32(i32, i32) nounwind readnone
declare i64 @llvm.x86.bmi.bextr.64(i64, i64) nounwind readnone
define i32 @test_x86_tbm_bextri_u32(i32 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u32(
; CHECK-NEXT: [[TMP1:%.*]] = tail call i32 @llvm.x86.tbm.bextri.u32(i32 [[A:%.*]], i32 1296)
; CHECK-NEXT: ret i32 [[TMP1]]
;
%1 = tail call i32 @llvm.x86.tbm.bextri.u32(i32 %a, i32 1296)
ret i32 %1
}
define i32 @test_x86_tbm_bextri_u32_zero_length(i32 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u32_zero_length(
; CHECK-NEXT: ret i32 0
;
%1 = tail call i32 @llvm.x86.tbm.bextri.u32(i32 %a, i32 1)
ret i32 %1
}
define i32 @test_x86_tbm_bextri_u32_large_shift(i32 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u32_large_shift(
; CHECK-NEXT: ret i32 0
;
%1 = tail call i32 @llvm.x86.tbm.bextri.u32(i32 %a, i32 288)
ret i32 %1
}
define i64 @test_x86_tbm_bextri_u64(i64 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u64(
; CHECK-NEXT: [[TMP1:%.*]] = tail call i64 @llvm.x86.tbm.bextri.u64(i64 [[A:%.*]], i64 1312)
; CHECK-NEXT: ret i64 [[TMP1]]
;
%1 = tail call i64 @llvm.x86.tbm.bextri.u64(i64 %a, i64 1312)
ret i64 %1
}
define i64 @test_x86_tbm_bextri_u64_zero_length(i64 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u64_zero_length(
; CHECK-NEXT: ret i64 0
;
%1 = tail call i64 @llvm.x86.tbm.bextri.u64(i64 %a, i64 1)
ret i64 %1
}
define i64 @test_x86_tbm_bextri_u64_large_shift(i64 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u64_large_shift(
; CHECK-NEXT: ret i64 0
;
%1 = tail call i64 @llvm.x86.tbm.bextri.u64(i64 %a, i64 320)
ret i64 %1
}
define i32 @test_x86_tbm_bextri_u32_constfold() nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u32_constfold(
; CHECK-NEXT: ret i32 57005
;
%1 = tail call i32 @llvm.x86.tbm.bextri.u32(i32 3735928559, i32 4112) ; extract bits 31:16 from 0xDEADBEEF
ret i32 %1
}
define i32 @test_x86_tbm_bextri_u32_constfold2() nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u32_constfold2(
; CHECK-NEXT: ret i32 233495534
;
%1 = tail call i32 @llvm.x86.tbm.bextri.u32(i32 3735928559, i32 8196) ; extract bits 35:4 from 0xDEADBEEF
ret i32 %1
}
define i32 @test_x86_tbm_bextri_u32_constfold3() nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u32_constfold3(
; CHECK-NEXT: ret i32 233495534
;
%1 = tail call i32 @llvm.x86.tbm.bextri.u32(i32 3735928559, i32 16388) ; extract bits 67:4 from 0xDEADBEEF
ret i32 %1
}
define i64 @test_x86_tbm_bextri_u64_constfold() nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u64_constfold(
; CHECK-NEXT: ret i64 57005
;
%1 = tail call i64 @llvm.x86.tbm.bextri.u64(i64 3735928559, i64 4112) ; extract bits 31:16 from 0xDEADBEEF
ret i64 %1
}
define i64 @test_x86_tbm_bextri_u64_constfold2() nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u64_constfold2(
; CHECK-NEXT: ret i64 233495534
;
%1 = tail call i64 @llvm.x86.tbm.bextri.u64(i64 3735928559, i64 16388) ; extract bits 67:4 from 0xDEADBEEF
ret i64 %1
}
define i64 @test_x86_tbm_bextri_u64_constfold3() nounwind readnone {
; CHECK-LABEL: @test_x86_tbm_bextri_u64_constfold3(
; CHECK-NEXT: ret i64 233495534
;
%1 = tail call i64 @llvm.x86.tbm.bextri.u64(i64 3735928559, i64 32772) ; extract bits 131:4 from 0xDEADBEEF
ret i64 %1
}
define i32 @test_x86_bmi_bextri_32(i32 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_32(
; CHECK-NEXT: [[TMP1:%.*]] = tail call i32 @llvm.x86.bmi.bextr.32(i32 [[A:%.*]], i32 1296)
; CHECK-NEXT: ret i32 [[TMP1]]
;
%1 = tail call i32 @llvm.x86.bmi.bextr.32(i32 %a, i32 1296)
ret i32 %1
}
define i32 @test_x86_bmi_bextri_32_zero_length(i32 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_32_zero_length(
; CHECK-NEXT: ret i32 0
;
%1 = tail call i32 @llvm.x86.bmi.bextr.32(i32 %a, i32 1)
ret i32 %1
}
define i32 @test_x86_bmi_bextri_32_large_shift(i32 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_32_large_shift(
; CHECK-NEXT: ret i32 0
;
%1 = tail call i32 @llvm.x86.bmi.bextr.32(i32 %a, i32 288)
ret i32 %1
}
define i64 @test_x86_bmi_bextri_64(i64 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_64(
; CHECK-NEXT: [[TMP1:%.*]] = tail call i64 @llvm.x86.bmi.bextr.64(i64 [[A:%.*]], i64 1312)
; CHECK-NEXT: ret i64 [[TMP1]]
;
%1 = tail call i64 @llvm.x86.bmi.bextr.64(i64 %a, i64 1312)
ret i64 %1
}
define i64 @test_x86_bmi_bextri_64_zero_length(i64 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_64_zero_length(
; CHECK-NEXT: ret i64 0
;
%1 = tail call i64 @llvm.x86.bmi.bextr.64(i64 %a, i64 1)
ret i64 %1
}
define i64 @test_x86_bmi_bextri_64_large_shift(i64 %a) nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_64_large_shift(
; CHECK-NEXT: ret i64 0
;
%1 = tail call i64 @llvm.x86.bmi.bextr.64(i64 %a, i64 320)
ret i64 %1
}
define i32 @test_x86_bmi_bextri_32_constfold() nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_32_constfold(
; CHECK-NEXT: ret i32 57005
;
%1 = tail call i32 @llvm.x86.bmi.bextr.32(i32 3735928559, i32 4112) ; extract bits 31:16 from 0xDEADBEEF
ret i32 %1
}
define i32 @test_x86_bmi_bextri_32_constfold2() nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_32_constfold2(
; CHECK-NEXT: ret i32 233495534
;
%1 = tail call i32 @llvm.x86.bmi.bextr.32(i32 3735928559, i32 8196) ; extract bits 35:4 from 0xDEADBEEF
ret i32 %1
}
define i32 @test_x86_bmi_bextri_32_constfold3() nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_32_constfold3(
; CHECK-NEXT: ret i32 233495534
;
%1 = tail call i32 @llvm.x86.bmi.bextr.32(i32 3735928559, i32 16388) ; extract bits 67:4 from 0xDEADBEEF
ret i32 %1
}
define i64 @test_x86_bmi_bextri_64_constfold() nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_64_constfold(
; CHECK-NEXT: ret i64 57005
;
%1 = tail call i64 @llvm.x86.bmi.bextr.64(i64 3735928559, i64 4112) ; extract bits 31:16 from 0xDEADBEEF
ret i64 %1
}
define i64 @test_x86_bmi_bextri_64_constfold2() nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_64_constfold2(
; CHECK-NEXT: ret i64 233495534
;
%1 = tail call i64 @llvm.x86.bmi.bextr.64(i64 3735928559, i64 16388) ; extract bits 67:4 from 0xDEADBEEF
ret i64 %1
}
define i64 @test_x86_bmi_bextri_64_constfold3() nounwind readnone {
; CHECK-LABEL: @test_x86_bmi_bextri_64_constfold3(
; CHECK-NEXT: ret i64 233495534
;
%1 = tail call i64 @llvm.x86.bmi.bextr.64(i64 3735928559, i64 32772) ; extract bits 131:4 from 0xDEADBEEF
ret i64 %1
}