[polly] r252157 - Fix escaping value to subregion entry node phi

[Michael Kruse via llvm-commits]

Author: meinersbur
Date: Thu Nov  5 07:18:43 2015
New Revision: 252157

URL: http://llvm.org/viewvc/llvm-project?rev=252157&view=rev
Log:
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.

Added:
    polly/trunk/test/ScopInfo/out-of-scop-use-in-region-entry-phi-node-nonaffine-subregion.ll   (with props)
Modified:
    polly/trunk/lib/Analysis/ScopInfo.cpp

Modified: polly/trunk/lib/Analysis/ScopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopInfo.cpp?rev=252157&r1=252156&r2=252157&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopInfo.cpp (original)
+++ polly/trunk/lib/Analysis/ScopInfo.cpp Thu Nov  5 07:18:43 2015
@@ -3342,6 +3342,27 @@ bool ScopInfo::buildScalarDependences(In
     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(In
       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)

Added: polly/trunk/test/ScopInfo/out-of-scop-use-in-region-entry-phi-node-nonaffine-subregion.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/ScopInfo/out-of-scop-use-in-region-entry-phi-node-nonaffine-subregion.ll?rev=252157&view=auto
==============================================================================
--- polly/trunk/test/ScopInfo/out-of-scop-use-in-region-entry-phi-node-nonaffine-subregion.ll (added)
+++ polly/trunk/test/ScopInfo/out-of-scop-use-in-region-entry-phi-node-nonaffine-subregion.ll Thu Nov  5 07:18:43 2015
@@ -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
+}

Propchange: polly/trunk/test/ScopInfo/out-of-scop-use-in-region-entry-phi-node-nonaffine-subregion.ll
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    svn:executable = *