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| author | Eli Friedman <eli.friedman@gmail.com> | 2009-12-17 06:07:04 +0000 |
|---|---|---|
| committer | Eli Friedman <eli.friedman@gmail.com> | 2009-12-17 06:07:04 +0000 |
| commit | e8e17833bec5943dffe5f89546465f94d8277ad6 (patch) | |
| tree | 1034bb297b1178ce5d28eb4a7b8fe4533a8a9c15 | |
| parent | 266d945fff195c65e46b1226eb7ee95a632b5e58 (diff) | |
| download | llvm-e8e17833bec5943dffe5f89546465f94d8277ad6.tar.gz llvm-e8e17833bec5943dffe5f89546465f94d8277ad6.tar.bz2 llvm-e8e17833bec5943dffe5f89546465f94d8277ad6.tar.xz | |
Aggressively flip compare constant expressions where appropriate; constant
folding in particular expects null to be on the RHS.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91587 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/VMCore/ConstantFold.cpp | 8 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/constant-fold-compare.ll | 8 |
2 files changed, 13 insertions, 3 deletions
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index 7f713d15c6..2449739aaf 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -1839,14 +1839,16 @@ Constant *llvm::ConstantFoldCompareInstruction(LLVMContext &Context, } } - if (!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) { + if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) || + (C1->isNullValue() && !C2->isNullValue())) { // If C2 is a constant expr and C1 isn't, flip them around and fold the // other way if possible. + // Also, if C1 is null and C2 isn't, flip them around. switch (pred) { case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_NE: // No change of predicate required. - return ConstantFoldCompareInstruction(Context, pred, C2, C1); + return ConstantExpr::getICmp(pred, C2, C1); case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_SLT: @@ -1858,7 +1860,7 @@ Constant *llvm::ConstantFoldCompareInstruction(LLVMContext &Context, case ICmpInst::ICMP_SGE: // Change the predicate as necessary to swap the operands. pred = ICmpInst::getSwappedPredicate((ICmpInst::Predicate)pred); - return ConstantFoldCompareInstruction(Context, pred, C2, C1); + return ConstantExpr::getICmp(pred, C2, C1); default: // These predicates cannot be flopped around. break; diff --git a/test/Transforms/InstCombine/constant-fold-compare.ll b/test/Transforms/InstCombine/constant-fold-compare.ll new file mode 100644 index 0000000000..6e41e2f680 --- /dev/null +++ b/test/Transforms/InstCombine/constant-fold-compare.ll @@ -0,0 +1,8 @@ +; RUN: opt < %s -instcombine -S | FileCheck %s +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32" + +define i32 @a() nounwind readnone { +entry: + ret i32 zext (i1 icmp eq (i32 0, i32 ptrtoint (i32 ()* @a to i32)) to i32) +} +; CHECK: ret i32 0 |