[llvm-commits] [llvm] r168245 - in /llvm/trunk: lib/Analysis/BasicAliasAnalysis.cpp test/Analysis/BasicAA/phi-spec-order.ll
Hal Finkel
hfinkel at anl.gov
Fri Nov 16 18:33:15 PST 2012
Author: hfinkel
Date: Fri Nov 16 20:33:15 2012
New Revision: 168245
URL: http://llvm.org/viewvc/llvm-project?rev=168245&view=rev
Log:
Phi speculation improvement for BasicAA
This is a partial solution to PR14351. It removes some of the special
significance of the first incoming phi value in the phi aliasing checking logic
in BasicAA. In the context of a loop, the old logic assumes that the first
incoming value is the interesting one (meaning that it is the one that comes
from outside the loop), but this is often not the case. With this change, we
now test first the incoming value that comes from a block other than the parent
of the phi being tested.
Added:
llvm/trunk/test/Analysis/BasicAA/phi-spec-order.ll
Modified:
llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=168245&r1=168244&r2=168245&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Fri Nov 16 20:33:15 2012
@@ -1065,9 +1065,15 @@
if (PN > V2)
std::swap(Locs.first, Locs.second);
+ // Find the first incoming phi value not from its parent.
+ unsigned f = 0;
+ while (PN->getIncomingBlock(f) == PN->getParent() &&
+ f < PN->getNumIncomingValues()-1)
+ ++f;
+
AliasResult Alias =
- aliasCheck(PN->getIncomingValue(0), PNSize, PNTBAAInfo,
- PN2->getIncomingValueForBlock(PN->getIncomingBlock(0)),
+ aliasCheck(PN->getIncomingValue(f), PNSize, PNTBAAInfo,
+ PN2->getIncomingValueForBlock(PN->getIncomingBlock(f)),
V2Size, V2TBAAInfo);
if (Alias == MayAlias)
return MayAlias;
@@ -1096,7 +1102,10 @@
ArePhisAssumedNoAlias = true;
}
- for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) {
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
+ if (i == f)
+ continue;
+
AliasResult ThisAlias =
aliasCheck(PN->getIncomingValue(i), PNSize, PNTBAAInfo,
PN2->getIncomingValueForBlock(PN->getIncomingBlock(i)),
Added: llvm/trunk/test/Analysis/BasicAA/phi-spec-order.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/phi-spec-order.ll?rev=168245&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/phi-spec-order.ll (added)
+++ llvm/trunk/test/Analysis/BasicAA/phi-spec-order.ll Fri Nov 16 20:33:15 2012
@@ -0,0 +1,71 @@
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
+target triple = "powerpc64-bgq-linux"
+; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
+
+ at X = external global [16000 x double], align 32
+ at Y = external global [16000 x double], align 32
+
+define signext i32 @s000() nounwind {
+entry:
+ br label %for.cond2.preheader
+
+for.cond2.preheader: ; preds = %for.end, %entry
+ %nl.018 = phi i32 [ 0, %entry ], [ %inc9, %for.end ]
+ br label %for.body4
+
+for.body4: ; preds = %for.body4, %for.cond2.preheader
+ %lsr.iv4 = phi [16000 x double]* [ %i11, %for.body4 ], [ bitcast (double* getelementptr inbounds ([16000 x double]* @Y, i64 0, i64 8)
+ to [16000 x double]*), %for.cond2.preheader ]
+ %lsr.iv1 = phi [16000 x double]* [ %i10, %for.body4 ], [ @X, %for.cond2.preheader ]
+
+; CHECK: NoAlias:{{[ \t]+}}[16000 x double]* %lsr.iv1, [16000 x double]* %lsr.iv4
+
+ %lsr.iv = phi i32 [ %lsr.iv.next, %for.body4 ], [ 16000, %for.cond2.preheader ]
+ %lsr.iv46 = bitcast [16000 x double]* %lsr.iv4 to <4 x double>*
+ %lsr.iv12 = bitcast [16000 x double]* %lsr.iv1 to <4 x double>*
+ %scevgep11 = getelementptr <4 x double>* %lsr.iv46, i64 -2
+ %i6 = load <4 x double>* %scevgep11, align 32, !tbaa !0
+ %add = fadd <4 x double> %i6, <double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00>
+ store <4 x double> %add, <4 x double>* %lsr.iv12, align 32, !tbaa !0
+ %scevgep10 = getelementptr <4 x double>* %lsr.iv46, i64 -1
+ %i7 = load <4 x double>* %scevgep10, align 32, !tbaa !0
+ %add.4 = fadd <4 x double> %i7, <double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00>
+ %scevgep9 = getelementptr <4 x double>* %lsr.iv12, i64 1
+ store <4 x double> %add.4, <4 x double>* %scevgep9, align 32, !tbaa !0
+ %i8 = load <4 x double>* %lsr.iv46, align 32, !tbaa !0
+ %add.8 = fadd <4 x double> %i8, <double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00>
+ %scevgep8 = getelementptr <4 x double>* %lsr.iv12, i64 2
+ store <4 x double> %add.8, <4 x double>* %scevgep8, align 32, !tbaa !0
+ %scevgep7 = getelementptr <4 x double>* %lsr.iv46, i64 1
+ %i9 = load <4 x double>* %scevgep7, align 32, !tbaa !0
+ %add.12 = fadd <4 x double> %i9, <double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00>
+ %scevgep3 = getelementptr <4 x double>* %lsr.iv12, i64 3
+ store <4 x double> %add.12, <4 x double>* %scevgep3, align 32, !tbaa !0
+
+; CHECK: NoAlias:{{[ \t]+}}<4 x double>* %scevgep11, <4 x double>* %scevgep7
+; CHECK: NoAlias:{{[ \t]+}}<4 x double>* %scevgep10, <4 x double>* %scevgep7
+; CHECK: NoAlias:{{[ \t]+}}<4 x double>* %scevgep7, <4 x double>* %scevgep9
+; CHECK: NoAlias:{{[ \t]+}}<4 x double>* %scevgep11, <4 x double>* %scevgep3
+; CHECK: NoAlias:{{[ \t]+}}<4 x double>* %scevgep10, <4 x double>* %scevgep3
+; CHECK: NoAlias:{{[ \t]+}}<4 x double>* %scevgep3, <4 x double>* %scevgep9
+
+ %lsr.iv.next = add i32 %lsr.iv, -16
+ %scevgep = getelementptr [16000 x double]* %lsr.iv1, i64 0, i64 16
+ %i10 = bitcast double* %scevgep to [16000 x double]*
+ %scevgep5 = getelementptr [16000 x double]* %lsr.iv4, i64 0, i64 16
+ %i11 = bitcast double* %scevgep5 to [16000 x double]*
+ %exitcond.15 = icmp eq i32 %lsr.iv.next, 0
+ br i1 %exitcond.15, label %for.end, label %for.body4
+
+for.end: ; preds = %for.body4
+ %inc9 = add nsw i32 %nl.018, 1
+ %exitcond = icmp eq i32 %inc9, 400000
+ br i1 %exitcond, label %for.end10, label %for.cond2.preheader
+
+for.end10: ; preds = %for.end
+ ret i32 0
+}
+
+!0 = metadata !{metadata !"double", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA"}
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