[llvm] r239139 - Revert "[InstCombine] Don't miscompile safe increment idiom"
Daniel Jasper
djasper at google.com
Fri Jun 5 02:31:20 PDT 2015
Author: djasper
Date: Fri Jun 5 04:31:20 2015
New Revision: 239139
URL: http://llvm.org/viewvc/llvm-project?rev=239139&view=rev
Log:
Revert "[InstCombine] Don't miscompile safe increment idiom"
This is breaking a lot of build bots and is causing very long-running
compiles (infinite loops)?
Likely, we shouldn't return nullptr?
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
llvm/trunk/test/Transforms/InstCombine/select.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp?rev=239139&r1=239138&r2=239139&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp Fri Jun 5 04:31:20 2015
@@ -292,28 +292,10 @@ static Value *SimplifyWithOpReplaced(Val
// If this is a binary operator, try to simplify it with the replaced op.
if (BinaryOperator *B = dyn_cast<BinaryOperator>(I)) {
- Value *Simplified = nullptr;
if (B->getOperand(0) == Op)
- Simplified =
- SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), DL, TLI);
- if (!Simplified && B->getOperand(1) == Op)
- Simplified =
- SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, DL, TLI);
- if (Simplified) {
- // Consider:
- // %cmp = icmp eq i32 %x, 2147483647
- // %add = add nsw i32 %x, 1
- // %sel = select i1 %cmp, i32 -2147483648, i32 %add
- //
- // We can't replace %sel with %add unless we strip away the flags.
- if (isa<OverflowingBinaryOperator>(B)) {
- B->setHasNoSignedWrap(false);
- B->setHasNoUnsignedWrap(false);
- }
- if (isa<PossiblyExactOperator>(B))
- B->setIsExact(false);
- }
- return Simplified;
+ return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), DL, TLI);
+ if (B->getOperand(1) == Op)
+ return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, DL, TLI);
}
// Same for CmpInsts.
Modified: llvm/trunk/test/Transforms/InstCombine/select.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/select.ll?rev=239139&r1=239138&r2=239139&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/select.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/select.ll Fri Jun 5 04:31:20 2015
@@ -1532,13 +1532,3 @@ define i32 @test_max_of_min(i32 %a) {
%s1 = select i1 %c1, i32 %s0, i32 -1
ret i32 %s1
}
-
-define i32 @PR23757(i32 %x) {
-; CHECK-LABEL: @PR23757
-; CHECK: %[[add:.*]] = add i32 %x, 1
-; CHECK-NEXT: ret i32 %[[add]]
- %cmp = icmp eq i32 %x, 2147483647
- %add = add nsw i32 %x, 1
- %sel = select i1 %cmp, i32 -2147483648, i32 %add
- ret i32 %sel
-}
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