; RUN: opt < %s -passes=instcombine -S | grep "align 32" | count 2 ; It's tempting to have an instcombine in which the src pointer of a ; memcpy is aligned up to the alignment of the destination, however ; there are pitfalls. If the src is an alloca, aligning it beyond what ; the target's stack pointer is aligned at will require dynamic ; stack realignment, which can require functions that don't otherwise ; need a frame pointer to need one. ; ; Abstaining from this transform is not the only way to approach this ; issue. Some late phase could be smart enough to reduce alloca ; alignments when they are greater than they need to be. Or, codegen ; could do dynamic alignment for just the one alloca, and leave the ; main stack pointer at its standard alignment. ; @dst = global [1024 x i8] zeroinitializer, align 32 define void @foo() nounwind { entry: %src = alloca [1024 x i8], align 64 %src1 = getelementptr [1024 x i8], [1024 x i8]* %src, i32 0, i32 0 call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 32 getelementptr inbounds ([1024 x i8], [1024 x i8]* @dst, i32 0, i32 0), i8* align 32 %src1, i32 1024, i1 false) call void @frob(i8* %src1) nounwind ret void } declare void @frob(i8*) declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i1) nounwind