diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 4c39485b935..a2658b3e3f1 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -7927,6 +7927,22 @@ Instruction *InstCombiner::commonPointerCastTransforms(CastInst &CI) { return commonCastTransforms(CI); } +/// isSafeIntegerType - Return true if this is a basic integer type, not a crazy +/// type like i42. We don't want to introduce operations on random non-legal +/// integer types where they don't already exist in the code. In the future, +/// we should consider making this based off target-data, so that 32-bit targets +/// won't get i64 operations etc. +static bool isSafeIntegerType(const Type *Ty) { + switch (Ty->getPrimitiveSizeInBits()) { + case 8: + case 16: + case 32: + case 64: + return true; + default: + return false; + } +} /// Only the TRUNC, ZEXT, SEXT, and BITCAST can both operand and result as /// integer types. This function implements the common transforms for all those @@ -7956,6 +7972,10 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) { // Attempt to propagate the cast into the instruction for int->int casts. int NumCastsRemoved = 0; if (!isa<BitCastInst>(CI) && + // Only do this if the dest type is a simple type, don't convert the + // expression tree to something weird like i93 unless the source is also + // strange. + (isSafeIntegerType(DestTy) || !isSafeIntegerType(SrcI->getType())) && CanEvaluateInDifferentType(SrcI, cast<IntegerType>(DestTy), CI.getOpcode(), NumCastsRemoved)) { // If this cast is a truncate, evaluting in a different type always |
