The logic that folds loads of static initializers doesn't take into account whether the variable being initialized may be modified at runtime. Here's a patch that fixes it: Index: SelectionDAGISel.cpp =================================================================== RCS file: /var/cvs/llvm/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp,v retrieving revision 1.319 diff -u -r1.319 SelectionDAGISel.cpp --- SelectionDAGISel.cpp +++ SelectionDAGISel.cpp @@ -3298,7 +3298,7 @@ } if (G) { GlobalVariable *GV = dyn_cast<GlobalVariable>(G->getGlobal()); - if (GV) { + if (GV && GV->isConstant()) { Str = GV->getStringValue(false); if (!Str.empty()) { CopyFromStr = true; And here's a testcase that reproduces it: target datalayout = "e-p:32:32" target endian = little target pointersize = 32 target triple = "i686-pc-linux-gnu" %fmt = global [4 x sbyte] c"%x\0A\00" %bytes = global [4 x sbyte] c"\AA\BB\CC\DD" implementation void %foo() { %y = alloca uint %c = cast uint* %y to sbyte* %z = getelementptr [4 x sbyte]* %bytes, int 0, int 0 call void %llvm.memcpy.i32( sbyte* %c, sbyte* %z, uint 4, uint 1 ) %r = load uint* %y %t = cast [4 x sbyte]* %fmt to sbyte* %tmp = call int (sbyte*, ...)* %printf( sbyte* %t, uint %r ) ret void } declare void %llvm.memcpy.i32(sbyte*, sbyte*, uint, uint) declare int %printf(sbyte*, ...)
Patch applied. Thanks!