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InstCombine: Don't strip convergent from intrinsic callsites
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Authored by arsenm on Jun 10 2016, 4:20 PM.

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Summary

Specific instances of intrinsic calls may want to be convergent, such as certain register reads but the intrinsic declaration is not.

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arsenm updated this revision to Diff 60424.Jun 10 2016, 4:20 PM

arsenm retitled this revision from to InstCombine: Don't strip convergent from intrinsic callsites.

arsenm updated this object.

arsenm added a subscriber: llvm-commits.

• tstellarAMD added a reviewer: majnemer.Jun 13 2016, 8:56 AM

ping

LGTM

This revision is now accepted and ready to land.Jun 20 2016, 10:34 AM

r273188

Revision Contents

Path

Size

lib/

Transforms/

InstCombine/

InstCombineCalls.cpp

3 lines

test/

Transforms/

InstCombine/

convergent.ll

11 lines

Diff 60424

lib/Transforms/InstCombine/InstCombineCalls.cpp

Show First 20 Lines • Show All 2,501 Lines • ▼ Show 20 Lines	Instruction *InstCombiner::visitCallSite(CallSite CS) {
// If the callee is a pointer to a function, attempt to move any casts to the		// If the callee is a pointer to a function, attempt to move any casts to the
// arguments of the call/invoke.		// arguments of the call/invoke.
Value *Callee = CS.getCalledValue();		Value *Callee = CS.getCalledValue();
if (!isa<Function>(Callee) && transformConstExprCastCall(CS))		if (!isa<Function>(Callee) && transformConstExprCastCall(CS))
return nullptr;		return nullptr;

if (Function *CalleeF = dyn_cast<Function>(Callee)) {		if (Function *CalleeF = dyn_cast<Function>(Callee)) {
// Remove the convergent attr on calls when the callee is not convergent.		// Remove the convergent attr on calls when the callee is not convergent.
if (CS.isConvergent() && !CalleeF->isConvergent()) {		if (CS.isConvergent() && !CalleeF->isConvergent() &&
		!CalleeF->isIntrinsic()) {
DEBUG(dbgs() << "Removing convergent attr from instr "		DEBUG(dbgs() << "Removing convergent attr from instr "
<< CS.getInstruction() << "\n");		<< CS.getInstruction() << "\n");
CS.setNotConvergent();		CS.setNotConvergent();
return CS.getInstruction();		return CS.getInstruction();
}		}

// If the call and callee calling conventions don't match, this call must		// If the call and callee calling conventions don't match, this call must
// be unreachable, as the call is undefined.		// be unreachable, as the call is undefined.
▲ Show 20 Lines • Show All 521 Lines • Show Last 20 Lines

test/Transforms/InstCombine/convergent.ll

	; RUN: opt -instcombine -S < %s \| FileCheck %s			; RUN: opt -instcombine -S < %s \| FileCheck %s

	declare i32 @k() convergent			declare i32 @k() convergent
	declare i32 @f()			declare i32 @f()

				declare i64 @llvm.read_register.i64(metadata) nounwind

	define i32 @extern() {			define i32 @extern() {
	; Convergent attr shouldn't be removed here; k is convergent.			; Convergent attr shouldn't be removed here; k is convergent.
	; CHECK: call i32 @k() [[CONVERGENT_ATTR:#[0-9]+]]			; CHECK: call i32 @k() [[CONVERGENT_ATTR:#[0-9]+]]
	%a = call i32 @k() convergent			%a = call i32 @k() convergent
	ret i32 %a			ret i32 %a
	}			}

	define i32 @extern_no_attr() {			define i32 @extern_no_attr() {
	Show All 11 Lines
	}			}

	define i32 @indirect_call(i32 ()* %f) {			define i32 @indirect_call(i32 ()* %f) {
	; CHECK call i32 %f() [[CONVERGENT_ATTR]]			; CHECK call i32 %f() [[CONVERGENT_ATTR]]
	%a = call i32 %f() convergent			%a = call i32 %f() convergent
	ret i32 %a			ret i32 %a
	}			}

				; do not remove from convergent intrinsic call sites
				; CHECK-LABEL: @convergent_intrinsic_call(
				; CHECK: call i64 @llvm.read_register.i64(metadata !0) [[CONVERGENT_ATTR]]
				define i64 @convergent_intrinsic_call() {
				%val = call i64 @llvm.read_register.i64(metadata !0) convergent
				ret i64 %val
				}

	; CHECK: [[CONVERGENT_ATTR]] = { convergent }			; CHECK: [[CONVERGENT_ATTR]] = { convergent }
				!0 = !{!"foo"}