From 2be921adc41fb079ce25d36bdd6402ca70d56451 Mon Sep 17 00:00:00 2001 From: "Arnaud A. de Grandmaison" Date: Fri, 22 Mar 2013 08:25:01 +0000 Subject: InstCombine: Improve the result bitvect type when folding (cmp pred (load (gep GV, i)) C) to a bit test. The original code used i32, and i64 if legal. This introduced unneeded casts when they aren't legal, or when the index variable i has another type. In order of preference: try to use i's type; use the smallest fitting legal type (using an added DataLayout method); default to i32. A testcase checks that this works when the index gep operand is i16. Patch by : Ahmed Bougacha Reviewed by : Duncan git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177712 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineCompares.cpp | 31 ++++++++++++++-------- 1 file changed, 20 insertions(+), 11 deletions(-) (limited to 'lib/Transforms/InstCombine/InstCombineCompares.cpp') diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index 32fdb9b..a4e117e 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -443,20 +443,29 @@ FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV, } - // If a 32-bit or 64-bit magic bitvector captures the entire comparison state + // If a magic bitvector captures the entire comparison state // of this load, replace it with computation that does: // ((magic_cst >> i) & 1) != 0 - if (ArrayElementCount <= 32 || - (TD && ArrayElementCount <= 64 && TD->isLegalInteger(64))) { - Type *Ty; - if (ArrayElementCount <= 32) + { + Type *Ty = 0; + + // Look for an appropriate type: + // - The type of Idx if the magic fits + // - The smallest fitting legal type if we have a DataLayout + // - Default to i32 + if (ArrayElementCount <= Idx->getType()->getIntegerBitWidth()) + Ty = Idx->getType(); + else if (TD) + Ty = TD->getSmallestLegalIntType(Init->getContext(), ArrayElementCount); + else if (ArrayElementCount <= 32) Ty = Type::getInt32Ty(Init->getContext()); - else - Ty = Type::getInt64Ty(Init->getContext()); - Value *V = Builder->CreateIntCast(Idx, Ty, false); - V = Builder->CreateLShr(ConstantInt::get(Ty, MagicBitvector), V); - V = Builder->CreateAnd(ConstantInt::get(Ty, 1), V); - return new ICmpInst(ICmpInst::ICMP_NE, V, ConstantInt::get(Ty, 0)); + + if (Ty != 0) { + Value *V = Builder->CreateIntCast(Idx, Ty, false); + V = Builder->CreateLShr(ConstantInt::get(Ty, MagicBitvector), V); + V = Builder->CreateAnd(ConstantInt::get(Ty, 1), V); + return new ICmpInst(ICmpInst::ICMP_NE, V, ConstantInt::get(Ty, 0)); + } } return 0; -- cgit v1.1