forked from OSchip/llvm-project
Use a combination of copyRegToReg and ISD::BIT_CONVERT when doing fast isel of bitcasts,
allowing it to support the full range of conversions people might ask for in a correct manner. llvm-svn: 55378
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@ -251,19 +251,30 @@ FastISel::SelectInstructions(BasicBlock::iterator Begin,
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// Unhandled type. Halt "fast" selection and bail.
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return I;
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// Otherwise, insert a register-to-register copy.
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TargetRegisterClass* SrcClass = TLI.getRegClassFor(SrcVT);
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TargetRegisterClass* DstClass = TLI.getRegClassFor(DstVT);
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unsigned Op0 = ValueMap[I->getOperand(0)];
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unsigned ResultReg = createResultReg(DstClass);
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if (Op0 == 0)
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// Unhandled operand. Halt "fast" selection and bail.
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return false;
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// First, try to perform the bitcast by inserting a reg-reg copy.
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unsigned ResultReg = 0;
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if (SrcVT.getSimpleVT() == DstVT.getSimpleVT()) {
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TargetRegisterClass* SrcClass = TLI.getRegClassFor(SrcVT);
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TargetRegisterClass* DstClass = TLI.getRegClassFor(DstVT);
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ResultReg = createResultReg(DstClass);
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bool InsertedCopy = TII.copyRegToReg(*MBB, MBB->end(), ResultReg,
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Op0, DstClass, SrcClass);
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if (!InsertedCopy)
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ResultReg = 0;
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}
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// If the reg-reg copy failed, select a BIT_CONVERT opcode.
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if (!ResultReg)
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ResultReg = FastEmit_r(SrcVT.getSimpleVT(), DstVT.getSimpleVT(),
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ISD::BIT_CONVERT, Op0);
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if (!ResultReg)
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return I;
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ValueMap[I] = ResultReg;
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