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Add a new icmp+select optz'n. Also shows off the load(cst) folding added in 

r140966.

llvm-svn: 140969
This commit is contained in:
Nick Lewycky 2011-10-02 10:37:37 +00:00
parent 9b0f5688b9
commit 99fb091f65
2 changed files with 16 additions and 0 deletions
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6
llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
View File

@ -482,10 +482,16 @@ Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI,
if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD) == TrueVal ||
SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD) == TrueVal)
return ReplaceInstUsesWith(SI, FalseVal);
if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD) == FalseVal ||
SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD) == FalseVal)
return ReplaceInstUsesWith(SI, FalseVal);
} else if (Pred == ICmpInst::ICMP_NE) {
if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD) == FalseVal ||
SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD) == FalseVal)
return ReplaceInstUsesWith(SI, TrueVal);
if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD) == TrueVal ||
SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD) == TrueVal)
return ReplaceInstUsesWith(SI, TrueVal);
}
// NOTE: if we wanted to, this is where to detect integer MIN/MAX

10
llvm/test/Transforms/InstCombine/select.ll
View File

@ -799,3 +799,13 @@ define i1 @test60(i32 %x, i1* %y) nounwind {
; CHECK: @test60
; CHECK: select
}
@glbl = constant i32 10
define i32 @test61(i32* %ptr) {
%A = load i32* %ptr
%B = icmp eq i32* %ptr, @glbl
%C = select i1 %B, i32 %A, i32 10
ret i32 %C
; CHECK: @test61
; CHECK: ret i32 10
}