From d59ae907eea28285ece6696d6f3271b4ca578c0d Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 26 Jan 2012 02:32:04 +0000
Subject: Continue improving support for ConstantDataAggregate, and use the new
 methods recently added to (sometimes greatly!) simplify code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149024 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../InstCombine/InstructionCombining.cpp           | 24 ++++++++--------------
 1 file changed, 8 insertions(+), 16 deletions(-)

(limited to 'lib/Transforms/InstCombine/InstructionCombining.cpp')

diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index af065cd886..86e491b571 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1270,24 +1270,16 @@ Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) {
     return ReplaceInstUsesWith(EV, Agg);
 
   if (Constant *C = dyn_cast<Constant>(Agg)) {
-    if (isa<UndefValue>(C))
-      return ReplaceInstUsesWith(EV, UndefValue::get(EV.getType()));
-      
-    if (isa<ConstantAggregateZero>(C))
-      return ReplaceInstUsesWith(EV, Constant::getNullValue(EV.getType()));
-
-    if (isa<ConstantArray>(C) || isa<ConstantStruct>(C)) {
-      // Extract the element indexed by the first index out of the constant
-      Value *V = C->getOperand(*EV.idx_begin());
-      if (EV.getNumIndices() > 1)
-        // Extract the remaining indices out of the constant indexed by the
-        // first index
-        return ExtractValueInst::Create(V, EV.getIndices().slice(1));
-      else
-        return ReplaceInstUsesWith(EV, V);
+    if (Constant *C2 = C->getAggregateElement(*EV.idx_begin())) {
+      if (EV.getNumIndices() == 0)
+        return ReplaceInstUsesWith(EV, C2);
+      // Extract the remaining indices out of the constant indexed by the
+      // first index
+      return ExtractValueInst::Create(C2, EV.getIndices().slice(1));
     }
     return 0; // Can't handle other constants
-  } 
+  }
+  
   if (InsertValueInst *IV = dyn_cast<InsertValueInst>(Agg)) {
     // We're extracting from an insertvalue instruction, compare the indices
     const unsigned *exti, *exte, *insi, *inse;
-- 
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