[polly] r307660 - [Simplify] Also remove redundant writes which originally came from PHI nodes

[Tobias Grosser via llvm-commits]

Author: grosser
Date: Tue Jul 11 07:29:39 2017
New Revision: 307660

URL: http://llvm.org/viewvc/llvm-project?rev=307660&view=rev
Log:
[Simplify] Also remove redundant writes which originally came from PHI nodes

Modified:
    polly/trunk/lib/Transform/Simplify.cpp
    polly/trunk/test/Simplify/gemm.ll

Modified: polly/trunk/lib/Transform/Simplify.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Transform/Simplify.cpp?rev=307660&r1=307659&r2=307660&view=diff
==============================================================================
--- polly/trunk/lib/Transform/Simplify.cpp (original)
+++ polly/trunk/lib/Transform/Simplify.cpp Tue Jul 11 07:29:39 2017
@@ -235,10 +235,17 @@ private:
           continue;
         if (!WA->isLatestArrayKind())
           continue;
-        if (!isa<StoreInst>(WA->getAccessInstruction()))
+        if (!isa<StoreInst>(WA->getAccessInstruction()) && !WA->isPHIKind())
           continue;
 
         auto ReadingValue = WA->getAccessValue();
+
+        if (WA->isPHIKind()) {
+          PHINode *PHI = cast<PHINode>(WA->getAccessValue());
+          BasicBlock *BB = Stmt.getBasicBlock();
+          ReadingValue = PHI->getIncomingValueForBlock(BB);
+        }
+
         if (!ReadingValue)
           continue;
 

Modified: polly/trunk/test/Simplify/gemm.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/Simplify/gemm.ll?rev=307660&r1=307659&r2=307660&view=diff
==============================================================================
--- polly/trunk/test/Simplify/gemm.ll (original)
+++ polly/trunk/test/Simplify/gemm.ll Tue Jul 11 07:29:39 2017
@@ -13,12 +13,6 @@
 ;    }
 
 ; CHECK:      After accesses {
-; CHECK-NEXT:     Stmt_bb8
-; CHECK-NEXT:             ReadAccess :=	[Reduction Type: NONE] [Scalar: 0]
-; CHECK-NEXT:                 { Stmt_bb8[i0, i1] -> MemRef_C[i0, i1] };
-; CHECK-NEXT:             MustWriteAccess :=	[Reduction Type: NONE] [Scalar: 1]
-; CHECK-NEXT:                 { Stmt_bb8[i0, i1] -> MemRef_tmp_0__phi[] };
-; CHECK-NEXT:            new: { Stmt_bb8[i0, i1] -> MemRef_C[i0, i1] };
 ; CHECK-NEXT:     Stmt_bb10
 ; CHECK-NEXT:             ReadAccess :=	[Reduction Type: NONE] [Scalar: 1]
 ; CHECK-NEXT:                 { Stmt_bb10[i0, i1, i2] -> MemRef_tmp_0__phi[] };