[SROA] Use a more direct way of determining whether we are processing

the destination operand or source operand of a memmove.

It so happens that it was impossible for SROA to try to rewrite
self-memmove where the operands are *identical*, because either such
a think is volatile (and we don't rewrite) or it is non-volatile, and we
don't even register it as a use of the alloca.

However, making the 'IsDest' test *rely* on this subtle fact is... Very
confusing for the reader. We should use the direct and readily available
test of the Use* which gives us concrete information about which operand
is being rewritten.

No functionality changed, I hope! ;]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202103 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2014-02-25 03:50:14 +00:00
parent 3d9b85c754
commit 2516e7fb22

View File

@ -2428,8 +2428,9 @@ private:
uint64_t NewBeginOffset = std::max(BeginOffset, NewAllocaBeginOffset);
uint64_t NewEndOffset = std::min(EndOffset, NewAllocaEndOffset);
assert(II.getRawSource() == OldPtr || II.getRawDest() == OldPtr);
bool IsDest = II.getRawDest() == OldPtr;
bool IsDest = &II.getRawDestUse() == OldUse;
assert(IsDest && II.getRawDest() == OldPtr ||
(!IsDest && II.getRawSource() == OldPtr));
// Compute the relative offset within the transfer.
unsigned IntPtrWidth = DL.getPointerSizeInBits();