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Implement support for simplifying vector comparisons by 0.0 and 1.0 like we

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do for scalars.  Patch contributed by Nicolas Capens

This also generalizes the previous xforms to work on long double, now that 
isExactlyValue works for long double.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54653 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-08-11 22:06:05 +00:00
parent 3b8a90686a
commit b8cd4d3d49
2 changed files with 27 additions and 6 deletions
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16
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -2480,10 +2480,17 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
// "In IEEE floating point, x*1 is not equivalent to x for nans. However,
// ANSI says we can drop signals, so we can do this anyway." (from GCC)
// We need a better interface for long double here.
if (Op1->getType() == Type::FloatTy || Op1->getType() == Type::DoubleTy)
if (Op1F->isExactlyValue(1.0))
return ReplaceInstUsesWith(I, Op0); // Eliminate 'mul double %X, 1.0'
if (Op1F->isExactlyValue(1.0))
return ReplaceInstUsesWith(I, Op0); // Eliminate 'mul double %X, 1.0'
} else if (isa<VectorType>(Op1->getType())) {
if (isa<ConstantAggregateZero>(Op1))
return ReplaceInstUsesWith(I, Op1);
// As above, vector X*splat(1.0) -> X in all defined cases.
if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1))
if (ConstantFP *F = dyn_cast_or_null<ConstantFP>(Op1V->getSplatValue()))
if (F->isExactlyValue(1.0))
return ReplaceInstUsesWith(I, Op0);
}
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0))
@ -11636,3 +11643,4 @@ FunctionPass *llvm::createInstructionCombiningPass() {
return new InstCombiner();
}

17
test/Transforms/InstCombine/mul.ll
View File

@ -1,7 +1,5 @@
; This test makes sure that mul instructions are properly eliminated.
;
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep mul
; END.
define i32 @test1(i32 %A) {
%B = mul i32 %A, 1 ; <i32> [#uses=1]
@ -78,3 +76,18 @@ define i32 @test12(i8 %a, i32 %b) {
ret i32 %e
}
; PR2642
define internal void @test13(<4 x float>*) {
load <4 x float>* %0, align 1
mul <4 x float> %2, < float 1.000000e+00, float 1.000000e+00, float 1.000000e+00, float 1.000000e+00 >
store <4 x float> %3, <4 x float>* %0, align 1
ret void
}
define internal void @test14(<4 x float>*) {
load <4 x float>* %0, align 1
mul <4 x float> %2, zeroinitializer
store <4 x float> %3, <4 x float>* %0, align 1
ret void
}