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Fix escaping value to subregion entry node phi 

An incoming value from a block the is not inside the scop is an
external use, even if the phi is inside the scop. A previous fix in
r251208 did not apply if the phi is inside a non-affine subregion. We
move the check for this phi case before the non-affine subregion check.

llvm-svn: 252157
This commit is contained in:
Michael Kruse 2015-11-05 13:18:43 +00:00
parent 94e1d5831b
commit f714d470d7
2 changed files with 75 additions and 21 deletions
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42
polly/lib/Analysis/ScopInfo.cpp
View File

@ -3342,6 +3342,27 @@ bool ScopInfo::buildScalarDependences(Instruction *Inst, Region *R,
if (UseParent == ParentBB && !isa<PHINode>(UI))
continue;
// Uses by PHI nodes in the entry node count as external uses in case the
// use is through an incoming block that is itself not contained in the
// region.
if (R->getEntry() == UseParent) {
if (auto *PHI = dyn_cast<PHINode>(UI)) {
bool ExternalUse = false;
for (unsigned i = 0; i < PHI->getNumIncomingValues(); i++) {
if (PHI->getIncomingValue(i) == Inst &&
!R->contains(PHI->getIncomingBlock(i))) {
ExternalUse = true;
break;
}
}
if (ExternalUse) {
AnyCrossStmtUse = true;
continue;
}
}
}
// Do not build scalar dependences inside a non-affine subregion.
if (NonAffineSubRegion && NonAffineSubRegion->contains(UseParent))
continue;
@ -3365,27 +3386,6 @@ bool ScopInfo::buildScalarDependences(Instruction *Inst, Region *R,
continue;
}
// Uses by PHI nodes in the entry node count as external uses in case the
// use is through an incoming block that is itself not contained in the
// region.
if (R->getEntry() == UseParent) {
if (auto *PHI = dyn_cast<PHINode>(UI)) {
bool ExternalUse = false;
for (unsigned i = 0; i < PHI->getNumIncomingValues(); i++) {
if (PHI->getIncomingValue(i) == Inst &&
!R->contains(PHI->getIncomingBlock(i))) {
ExternalUse = true;
break;
}
}
if (ExternalUse) {
AnyCrossStmtUse = true;
continue;
}
}
}
// If the instruction can be synthesized and the user is in the region
// we do not need to add scalar dependences.
if (canSynthesizeInst)

54
polly/test/ScopInfo/out-of-scop-use-in-region-entry-phi-node-nonaffine-subregion.ll Executable file
View File

@ -0,0 +1,54 @@
; RUN: opt %loadPolly -polly-codegen -S < %s | FileCheck %s
;
; Check whether %newval is identified as escaping value, even though it is used
; in a phi that is in the region. Non-affine subregion case.
;
; CHECK-LABEL: subregion_entry.region_entering:
; CHECK: %loop_carried.ph = phi float [ %newval.merge, %backedge ], [ undef, %entry ]
;
; CHECK-LABEL: polly.merge_new_and_old:
; CHECK: %newval.merge = phi float [ %newval.final_reload, %polly.stmt.polly.merge_new_and_old.exit ], [ %newval, %subregion_exit.region_exiting ]
;
; CHECK-LABEL: polly.start:
; CHECK: store float %loop_carried.ph, float* %loop_carried.phiops
;
; CHECK-LABEL: polly.stmt.subregion_entry.entry:
; CHECK: %loop_carried.phiops.reload = load float, float* %loop_carried.phiops
;
; CHECK-LABEL: polly.stmt.subregion_entry:
; CHECK: %polly.loop_carried = phi float [ %loop_carried.phiops.reload2, %polly.stmt.subregion_entry.entry ]
; CHECK: %p_newval = fadd float %polly.loop_carried, 1.000000e+00
;
; CHECK-LABEL: polly.stmt.polly.merge_new_and_old.exit:
; CHECK: %newval.final_reload = load float, float* %newval.s2a
define void @func() {
entry:
br label %subregion_entry
subregion_entry:
%loop_carried = phi float [ undef, %entry ], [ %newval, %backedge ]
%indvar = phi i32 [ 1, %entry ], [ %indvar_next, %backedge ]
%newval = fadd float %loop_carried, 1.0
%cmp = fcmp ogt float undef, undef
br i1 %cmp, label %subregion_if, label %subregion_exit
subregion_if:
br label %subregion_exit
subregion_exit:
br i1 undef, label %if_then, label %if_else
if_then:
br label %backedge
if_else:
br label %backedge
backedge:
%indvar_next = add nuw nsw i32 %indvar, 1
br i1 false, label %subregion_entry, label %exit
exit:
ret void
}