[Hexagon] Check vector elements for equivalence in the HexagonVectorLoopCarriedReuse pass

    
    If the two instructions being compared for equivalence have corresponding operands
    that are integer constants, then check their values to determine equivalence.
    
    Patch by Suyog Sarda!
    

llvm-svn: 314642

1 files changed, 16 insertions, 1 deletions

diff --git a/llvm/lib/Target/Hexagon/HexagonVectorLoopCarriedReuse.cpp b/llvm/lib/Target/Hexagon/HexagonVectorLoopCarriedReuse.cpp
index aeff5f8d3e4..a0fdc70e141 100644
--- a/llvm/lib/Target/Hexagon/HexagonVectorLoopCarriedReuse.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonVectorLoopCarriedReuse.cpp
@@ -340,6 +340,21 @@ bool HexagonVectorLoopCarriedReuse::isEquivalentOperation(Instruction *I1,
         return false;
     }
   }
+
+  // If both the Instructions are of Vector Type and any of the element
+  // is integer constant, check their values too for equivalence.
+  if (I1->getType()->isVectorTy() && I2->getType()->isVectorTy()) {
+    unsigned NumOperands = I1->getNumOperands();
+    for (unsigned i = 0; i < NumOperands; ++i) {
+      ConstantInt *C1 = dyn_cast<ConstantInt>(I1->getOperand(i));
+      ConstantInt *C2 = dyn_cast<ConstantInt>(I2->getOperand(i));
+      if(!C1) continue;
+      assert(C2);
+      if (C1->getSExtValue() != C2->getSExtValue())
+        return false;
+    }
+  }
+
   return true;
 }
 
@@ -520,7 +535,7 @@ bool HexagonVectorLoopCarriedReuse::doVLCR() {
   assert((CurLoop->getNumBlocks() == 1) &&
          "Can do VLCR only on single block loops");
 
-  bool Changed;
+  bool Changed = false;
   bool Continue;
 
   DEBUG(dbgs() << "Working on Loop: " << *CurLoop->getHeader() << "\n");