#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/Local.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CallSite.h"
if (ByValAlignment <= 1) // 0 = unspecified, 1 = no particular alignment.
return Arg;
- // See if the argument is a (bitcasted) pointer to an alloca. If so, we can
- // round up the alloca if needed.
- if (AllocaInst *AI = dyn_cast<AllocaInst>(Arg->stripPointerCasts())) {
- unsigned AIAlign = AI->getAlignment();
-
- // If the alloca is known at least aligned as much as the byval, we can do
- // this optimization.
- if (AIAlign >= ByValAlignment)
- return Arg;
-
- // If the alloca has a specified alignment that is less than the byval,
- // then we can safely bump it up.
- if (AIAlign) {
- AI->setAlignment(ByValAlignment);
- return Arg;
- }
-
- // If the alignment has an unspecified alignment, then we can only modify
- // it if we have TD information. Doing so without TD info could end up
- // with us rounding the alignment *down* accidentally, which is badness.
- if (IFI.TD) {
- AIAlign = std::max(ByValAlignment, IFI.TD->getPrefTypeAlignment(AggTy));
- AI->setAlignment(AIAlign);
- return Arg;
- }
- }
+ // If the pointer is already known to be sufficiently aligned, or if we can
+ // round it up to a larger alignment, then we don't need a temporary.
+ if (getOrEnforceKnownAlignment(Arg, ByValAlignment,
+ IFI.TD) >= ByValAlignment)
+ return Arg;
- // Otherwise, we have to make a memcpy to get a safe alignment, pretty lame.
+ // Otherwise, we have to make a memcpy to get a safe alignment. This is bad
+ // for code quality, but rarely happens and is required for correctness.
}
LLVMContext &Context = Arg->getContext();