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Fix an issue where we were reusing materializations of constants in blocks not dominated by the materialization. This is

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the simple fix, materializing the constant before every use.  It might be better to either track domination of uses or
to materialize all constants and the beginning of the function and let remat sort when to do materialization at uses.

llvm-svn: 55703
This commit is contained in:
Owen Anderson 2008-09-03 17:37:03 +00:00
parent ce2b476d8e
commit 906c590bb8
1 changed files with 15 additions and 9 deletions
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24
lib/CodeGen/SelectionDAG/FastISel.cpp
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@ -21,21 +21,26 @@
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
// Don't cache constant materializations. To do so would require
// tracking what uses they dominate. Non-constants, however, already
// have the SSA def-doms-use requirement enforced, so we can cache their
// computations.
unsigned FastISel::getRegForValue(Value *V,
DenseMap<const Value*, unsigned> &ValueMap) {
unsigned &Reg = ValueMap[V];
if (Reg != 0)
return Reg;
if (ValueMap.count(V))
return ValueMap[V];
MVT::SimpleValueType VT = TLI.getValueType(V->getType()).getSimpleVT();
if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
if (CI->getValue().getActiveBits() > 64)
return 0;
Reg = FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue());
// Don't cache constant materializations. To do so would require
// tracking what uses they dominate.
return FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue());
} else if (isa<ConstantPointerNull>(V)) {
Reg = FastEmit_i(VT, VT, ISD::Constant, 0);
return FastEmit_i(VT, VT, ISD::Constant, 0);
} else if (ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
Reg = FastEmit_f(VT, VT, ISD::ConstantFP, CF);
unsigned Reg = FastEmit_f(VT, VT, ISD::ConstantFP, CF);
if (!Reg) {
const APFloat &Flt = CF->getValueAPF();
@ -56,12 +61,13 @@ unsigned FastISel::getRegForValue(Value *V,
if (Reg == 0)
return 0;
}
return Reg;
} else if (isa<UndefValue>(V)) {
Reg = createResultReg(TLI.getRegClassFor(VT));
unsigned Reg = createResultReg(TLI.getRegClassFor(VT));
BuildMI(MBB, TII.get(TargetInstrInfo::IMPLICIT_DEF), Reg);
return Reg;
}
return Reg;
}
/// UpdateValueMap - Update the value map to include the new mapping for this