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
// 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
--- /dev/null
+; 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
+}