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[X86TTI] Make constant base pointers for getElementPtr opaque. 

If getElementPtr uses a constant as base pointer, then make the constant opaque.
This prevents constant folding it with the offset. The offset can usually be
encoded in the load/store instruction itself and the base address doesn't have
to be rematerialized several times.

llvm-svn: 204739
This commit is contained in:
Juergen Ributzka 2014-03-25 18:01:25 +00:00
parent 5eef98cf7a
commit 631c4914b2
1 changed files with 3 additions and 2 deletions
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5
llvm/lib/Target/X86/X86TargetTransformInfo.cpp
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@ -798,8 +798,9 @@ unsigned X86TTI::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
switch (Opcode) { switch (Opcode) {
default: return TCC_Free; default: return TCC_Free;
case Instruction::GetElementPtr: case Instruction::GetElementPtr:
if (Idx != 0) if (Idx == 0)
return TCC_Free; return 2 * TCC_Basic;
return TCC_Free;
case Instruction::Store: case Instruction::Store:
ImmIdx = 0; ImmIdx = 0;
break; break;