diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 20 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/2009-04-07-MulPromoteToI96.ll | 13 |
2 files changed, 33 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 4c39485b93..a2658b3e3f 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/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 diff --git a/test/Transforms/InstCombine/2009-04-07-MulPromoteToI96.ll b/test/Transforms/InstCombine/2009-04-07-MulPromoteToI96.ll new file mode 100644 index 0000000000..82f8762981 --- /dev/null +++ b/test/Transforms/InstCombine/2009-04-07-MulPromoteToI96.ll @@ -0,0 +1,13 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {mul i64} +; rdar://6762288 + +; Instcombine should not promote the mul to i96 because it is definitely +; not a legal type for the target, and we don't want a libcall. + +define i96 @test(i96 %a.4, i96 %b.2) { + %tmp1086 = trunc i96 %a.4 to i64 ; <i64> [#uses=1] + %tmp836 = trunc i96 %b.2 to i64 ; <i64> [#uses=1] + %mul185 = mul i64 %tmp1086, %tmp836 ; <i64> [#uses=1] + %tmp544 = zext i64 %mul185 to i96 ; <i96> [#uses=1] + ret i96 %tmp544 +} |