[ScopInfo] Make scalars used by PHIs in non-affine regions available

Normally this is ensured when adding PHI nodes, but as PHI node dependences
do not need to be added in case all incoming blocks are within the same
non-affine region, this was missed.

This corrects an issue visible in LNT's sqlite3, in case invariant load hoisting
was disabled.

llvm-svn: 278792

diff --git a/polly/lib/Analysis/ScopBuilder.cpp b/polly/lib/Analysis/ScopBuilder.cpp
index 1290419..a14033e 100644 (file)
--- a/polly/lib/Analysis/ScopBuilder.cpp
+++ b/polly/lib/Analysis/ScopBuilder.cpp
@@ -68,9 +68,14 @@ void ScopBuilder::buildPHIAccesses(PHINode *PHI, Region *NonAffineSubRegion,
     Value *Op = PHI->getIncomingValue(u);
     BasicBlock *OpBB = PHI->getIncomingBlock(u);
 
-    // Do not build scalar dependences inside a non-affine subregion.
-    if (NonAffineSubRegion && NonAffineSubRegion->contains(OpBB))
+    // Do not build PHI dependences inside a non-affine subregion, but make
+    // sure that the necessary scalar values are still made available.
+    if (NonAffineSubRegion && NonAffineSubRegion->contains(OpBB)) {
+      auto *OpInst = dyn_cast<Instruction>(Op);
+      if (!OpInst || !NonAffineSubRegion->contains(OpInst))
+        ensureValueRead(Op, OpBB);
       continue;
+    }
 
     OnlyNonAffineSubRegionOperands = false;
     ensurePHIWrite(PHI, OpBB, Op, IsExitBlock);

diff --git a/polly/test/ScopInfo/phi-in-non-affine-region.ll b/polly/test/ScopInfo/phi-in-non-affine-region.ll
new file mode 100644 (file)
index 0000000..584e5e2
--- /dev/null
+++ b/polly/test/ScopInfo/phi-in-non-affine-region.ll
@@ -0,0 +1,61 @@
+; RUN: opt %loadPolly -analyze -polly-scops < %s | FileCheck %s
+
+; Verify that 'tmp' is stored in bb1 and read by bb3, as it is needed as
+; incoming value for the tmp11 PHI node.
+
+; CHECK: Stmt_bb1
+; CHECK-NEXT:   Domain :=
+; CHECK-NEXT:       { Stmt_bb1[] };
+; CHECK-NEXT:   Schedule :=
+; CHECK-NEXT:       { Stmt_bb1[] -> [0] };
+; CHECK-NEXT:   ReadAccess :=  [Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT:       { Stmt_bb1[] -> MemRef_global[0] };
+; CHECK-NEXT:   MustWriteAccess :=     [Reduction Type: NONE] [Scalar: 1]
+; CHECK-NEXT:       { Stmt_bb1[] -> MemRef_tmp[] };
+; CHECK-NEXT: Stmt_bb3__TO__bb10
+; CHECK-NEXT:   Domain :=
+; CHECK-NEXT:       { Stmt_bb3__TO__bb10[] };
+; CHECK-NEXT:   Schedule :=
+; CHECK-NEXT:       { Stmt_bb3__TO__bb10[] -> [1] };
+; CHECK-NEXT:   ReadAccess :=  [Reduction Type: NONE] [Scalar: 1]
+; CHECK-NEXT:       { Stmt_bb3__TO__bb10[] -> MemRef_tmp[] };
+; CHECK-NEXT:   MustWriteAccess :=     [Reduction Type: NONE] [Scalar: 1]
+; CHECK-NEXT:       { Stmt_bb3__TO__bb10[] -> MemRef_tmp11[] };
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.hoge = type { double, double, i8, i8, i8 }
+
+@global = external local_unnamed_addr global %struct.hoge, align 8
+
+define void @widget() local_unnamed_addr {
+bb:
+  br label %bb1
+
+bb1:                                              ; preds = %bb
+  %tmp = load double, double* getelementptr inbounds (%struct.hoge, %struct.hoge* @global, i64 0, i32 0), align 8
+  br i1 false, label %bb3, label %bb2
+
+bb2:                                              ; preds = %bb1
+  br label %bb3
+
+bb3:                                              ; preds = %bb2, %bb1
+  br i1 false, label %bb8, label %bb4
+
+bb4:                                              ; preds = %bb3
+  br label %bb5
+
+bb5:                                              ; preds = %bb4
+  %tmp6 = and i32 undef, 16711680
+  %tmp7 = icmp eq i32 %tmp6, 0
+  br i1 %tmp7, label %bb8, label %bb10
+
+bb8:                                              ; preds = %bb5, %bb3
+  %tmp9 = phi double [ %tmp, %bb3 ], [ undef, %bb5 ]
+  br label %bb10
+
+bb10:                                             ; preds = %bb8, %bb5
+  %tmp11 = phi double [ undef, %bb5 ], [ %tmp9, %bb8 ]
+  ret void
+}