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ComputeSignBits: look through SELECT_CC, not just SELECT
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Authored by escha on Aug 28 2015, 10:04 AM.

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Details

Reviewers

majnemer
arsenm
resistor

Summary

Should be pretty trivial, just a copy-paste of the SELECT case.

Diff Detail

Repository: rL LLVM

Event Timeline

escha updated this revision to Diff 33438.Aug 28 2015, 10:04 AM

escha retitled this revision from to ComputeSignBits: look through SELECT_CC, not just SELECT.

escha updated this object.

escha set the repository for this revision to rL LLVM.

escha added reviewers: resistor, majnemer.

escha added a subscriber: llvm-commits.

LGTM.

Is it possible to construct a test with an in tree target?

This revision is now accepted and ready to land.Aug 28 2015, 10:16 AM

I'm not really sure; it only came up when experimenting with out-of-tree optimizations for a target that uses SELECT_CC and not SELECT. It should be identical code though.

escha abandoned this revision.Aug 29 2015, 4:05 PM

Revision Contents

Path

Size

lib/

CodeGen/

SelectionDAG/

SelectionDAG.cpp

5 lines

Diff 33438

lib/CodeGen/SelectionDAG/SelectionDAG.cpp

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	if (Tmp == 1) return 1; // Early out.	if (Tmp == 1) return 1; // Early out.
	Tmp2 = ComputeNumSignBits(Op.getOperand(2), Depth+1);	Tmp2 = ComputeNumSignBits(Op.getOperand(2), Depth+1);
	return std::min(Tmp, Tmp2);	return std::min(Tmp, Tmp2);
		case ISD::SELECT_CC:
		Tmp = ComputeNumSignBits(Op.getOperand(2), Depth+1);
		if (Tmp == 1) return 1; // Early out.
		Tmp2 = ComputeNumSignBits(Op.getOperand(3), Depth+1);
		return std::min(Tmp, Tmp2);
	case ISD::SMIN:	case ISD::SMIN:
	case ISD::SMAX:	case ISD::SMAX:
	case ISD::UMIN:	case ISD::UMIN:
Context not available.