diff options
| -rw-r--r-- | lib/Transforms/IPO/GlobalOpt.cpp | 8 | ||||
| -rw-r--r-- | test/Transforms/GlobalOpt/2009-03-07-PromotePtrToBool.ll | 17 |
2 files changed, 22 insertions, 3 deletions
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp index b93eb6b6d4..1d0993a761 100644 --- a/lib/Transforms/IPO/GlobalOpt.cpp +++ b/lib/Transforms/IPO/GlobalOpt.cpp @@ -1531,10 +1531,12 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) { const Type *GVElType = GV->getType()->getElementType(); // If GVElType is already i1, it is already shrunk. If the type of the GV is - // an FP value or vector, don't do this optimization because a select between - // them is very expensive and unlikely to lead to later simplification. + // an FP value, pointer or vector, don't do this optimization because a select + // between them is very expensive and unlikely to lead to later + // simplification. In these cases, we typically end up with "cond ? v1 : v2" + // where v1 and v2 both require constant pool loads, a big loss. if (GVElType == Type::Int1Ty || GVElType->isFloatingPoint() || - isa<VectorType>(GVElType)) + isa<PointerType>(GVElType) || isa<VectorType>(GVElType)) return false; // Walk the use list of the global seeing if all the uses are load or store. diff --git a/test/Transforms/GlobalOpt/2009-03-07-PromotePtrToBool.ll b/test/Transforms/GlobalOpt/2009-03-07-PromotePtrToBool.ll new file mode 100644 index 0000000000..8dba5b1c21 --- /dev/null +++ b/test/Transforms/GlobalOpt/2009-03-07-PromotePtrToBool.ll @@ -0,0 +1,17 @@ +; RUN: llvm-as < %s | opt -globalopt | llvm-dis | grep {@X = internal global i32} +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-f80:128:128" +target triple = "i386-apple-darwin7" +@X = internal global i32* null ; <i32**> [#uses=2] +@Y = internal global i32 0 ; <i32*> [#uses=1] + +define void @foo() nounwind { +entry: + store i32* @Y, i32** @X, align 4 + ret void +} + +define i32* @get() nounwind { +entry: + %0 = load i32** @X, align 4 ; <i32*> [#uses=1] + ret i32* %0 +} |