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Pull in r241142 from upstream llvm trunk (by David Majnemer):

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[SCCP] Turn loads of null into undef instead of zero initialized values

  Surprisingly, this is a correctness issue: the mmx type exists for
  calling convention purposes, LLVM doesn't have a zero representation for
  them.

  This partially fixes PR23999.

Pull in r241143 from upstream llvm trunk (by David Majnemer):

  [LoopUnroll] Use undef for phis with no value live

  We would create a phi node with a zero initialized operand instead of
  undef in the case where no value was originally available.  This was
  problematic for x86_mmx which has no null value.

These fix a "Cannot create a null constant of that type!" error when
compiling the graphics/sdl2_gfx port with MMX enabled.

Reported by:	amdmi3
This commit is contained in:
dim 2015-07-04 20:07:37 +00:00
parent ce6959baeb
commit d26c180162
2 changed files with 2 additions and 2 deletions
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2
contrib/llvm/lib/Transforms/Scalar/SCCP.cpp
View File

@ -1054,7 +1054,7 @@ void SCCPSolver::visitLoadInst(LoadInst &I) {
// load null -> null
if (isa<ConstantPointerNull>(Ptr) && I.getPointerAddressSpace() == 0)
return markConstant(IV, &I, Constant::getNullValue(I.getType()));
return markConstant(IV, &I, UndefValue::get(I.getType()));
// Transform load (constant global) into the value loaded.
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Ptr)) {

2
contrib/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
View File

@ -81,7 +81,7 @@ static void ConnectProlog(Loop *L, Value *BECount, unsigned Count,
if (L->contains(PN)) {
NewPN->addIncoming(PN->getIncomingValueForBlock(NewPH), OrigPH);
} else {
NewPN->addIncoming(Constant::getNullValue(PN->getType()), OrigPH);
NewPN->addIncoming(UndefValue::get(PN->getType()), OrigPH);
}
Value *V = PN->getIncomingValueForBlock(Latch);