[llvm] r303818 - [InstCombine] use m_APInt to allow icmp-mul-mul vector fold
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Wed May 24 15:58:17 PDT 2017
Author: spatel
Date: Wed May 24 17:58:17 2017
New Revision: 303818
URL: http://llvm.org/viewvc/llvm-project?rev=303818&view=rev
Log:
[InstCombine] use m_APInt to allow icmp-mul-mul vector fold
The swapped operands in the first test is a manifestation of an
inefficiency for vectors that doesn't exist for scalars because
the IRBuilder checks for an all-ones mask for scalars, but not
vectors.
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/trunk/test/Transforms/InstCombine/icmp.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=303818&r1=303817&r2=303818&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Wed May 24 17:58:17 2017
@@ -3052,26 +3052,27 @@ Instruction *InstCombiner::foldICmpBinOp
}
break;
}
- case Instruction::Mul:
+ case Instruction::Mul: {
if (!I.isEquality())
break;
- if (ConstantInt *CI = dyn_cast<ConstantInt>(BO0->getOperand(1))) {
- // a * Cst icmp eq/ne b * Cst --> a & Mask icmp b & Mask
- // Mask = -1 >> count-trailing-zeros(Cst).
- if (!CI->isZero() && !CI->isOne()) {
- const APInt &AP = CI->getValue();
- ConstantInt *Mask = ConstantInt::get(
- I.getContext(),
- APInt::getLowBitsSet(AP.getBitWidth(),
- AP.getBitWidth() - AP.countTrailingZeros()));
+ const APInt *C;
+ if (match(BO0->getOperand(1), m_APInt(C))) {
+ // icmp eq/ne (X * C), (Y * C) --> icmp (X & Mask), (Y & Mask)
+ // Mask = -1 >> count-trailing-zeros(C).
+ if (*C != 0 && *C != 1) {
+ // FIXME: If trailing zeros is 0, don't bother creating Mask.
+ Constant *Mask = ConstantInt::get(
+ BO0->getType(),
+ APInt::getLowBitsSet(C->getBitWidth(),
+ C->getBitWidth() - C->countTrailingZeros()));
Value *And1 = Builder->CreateAnd(BO0->getOperand(0), Mask);
Value *And2 = Builder->CreateAnd(BO1->getOperand(0), Mask);
return new ICmpInst(Pred, And1, And2);
}
}
break;
-
+ }
case Instruction::UDiv:
case Instruction::LShr:
if (I.isSigned() || !BO0->isExact() || !BO1->isExact())
Modified: llvm/trunk/test/Transforms/InstCombine/icmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=303818&r1=303817&r2=303818&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp.ll Wed May 24 17:58:17 2017
@@ -2920,9 +2920,7 @@ define i1 @eq_mul_constants(i32 %x, i32
define <2 x i1> @eq_mul_constants_splat(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @eq_mul_constants_splat(
-; CHECK-NEXT: [[A:%.*]] = mul <2 x i32> %x, <i32 5, i32 5>
-; CHECK-NEXT: [[B:%.*]] = mul <2 x i32> %y, <i32 5, i32 5>
-; CHECK-NEXT: [[C:%.*]] = icmp ne <2 x i32> [[A]], [[B]]
+; CHECK-NEXT: [[C:%.*]] = icmp ne <2 x i32> %y, %x
; CHECK-NEXT: ret <2 x i1> [[C]]
;
%A = mul <2 x i32> %x, <i32 5, i32 5>
@@ -2950,9 +2948,9 @@ define i1 @eq_mul_constants_with_tz(i32
define <2 x i1> @eq_mul_constants_with_tz_splat(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @eq_mul_constants_with_tz_splat(
-; CHECK-NEXT: [[A:%.*]] = mul <2 x i32> %x, <i32 12, i32 12>
-; CHECK-NEXT: [[B:%.*]] = mul <2 x i32> %y, <i32 12, i32 12>
-; CHECK-NEXT: [[C:%.*]] = icmp eq <2 x i32> [[A]], [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = xor <2 x i32> %x, %y
+; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i32> [[TMP1]], <i32 1073741823, i32 1073741823>
+; CHECK-NEXT: [[C:%.*]] = icmp eq <2 x i32> [[TMP2]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[C]]
;
%A = mul <2 x i32> %x, <i32 12, i32 12>
More information about the llvm-commits
mailing list