[llvm] r215184 - GlobalOpt: Optimize in the face of insertvalue/extractvalue

[David Majnemer]

Author: majnemer
Date: Fri Aug  8 00:50:43 2014
New Revision: 215184

URL: http://llvm.org/viewvc/llvm-project?rev=215184&view=rev
Log:
GlobalOpt: Optimize in the face of insertvalue/extractvalue

GlobalOpt didn't know how to simulate InsertValueInst or
ExtractValueInst.  Optimizing these is pretty straightforward.

N.B. This came up when looking at clang's IRGen for MS ABI member
pointers; they are represented as aggregates.

Modified:
    llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
    llvm/trunk/test/Transforms/GlobalOpt/constantfold-initializers.ll

Modified: llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp?rev=215184&r1=215183&r2=215184&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp Fri Aug  8 00:50:43 2014
@@ -2394,6 +2394,17 @@ bool Evaluator::EvaluateBlock(BasicBlock
                                            getVal(SI->getOperand(2)));
       DEBUG(dbgs() << "Found a Select! Simplifying: " << *InstResult
             << "\n");
+    } else if (auto *EVI = dyn_cast<ExtractValueInst>(CurInst)) {
+      InstResult = ConstantExpr::getExtractValue(
+          getVal(EVI->getAggregateOperand()), EVI->getIndices());
+      DEBUG(dbgs() << "Found an ExtractValueInst! Simplifying: " << *InstResult
+                   << "\n");
+    } else if (auto *IVI = dyn_cast<InsertValueInst>(CurInst)) {
+      InstResult = ConstantExpr::getInsertValue(
+          getVal(IVI->getAggregateOperand()),
+          getVal(IVI->getInsertedValueOperand()), IVI->getIndices());
+      DEBUG(dbgs() << "Found an InsertValueInst! Simplifying: " << *InstResult
+                   << "\n");
     } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(CurInst)) {
       Constant *P = getVal(GEP->getOperand(0));
       SmallVector<Constant*, 8> GEPOps;

Modified: llvm/trunk/test/Transforms/GlobalOpt/constantfold-initializers.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalOpt/constantfold-initializers.ll?rev=215184&r1=215183&r2=215184&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/GlobalOpt/constantfold-initializers.ll (original)
+++ llvm/trunk/test/Transforms/GlobalOpt/constantfold-initializers.ll Fri Aug  8 00:50:43 2014
@@ -81,10 +81,23 @@ entry:
   ret void
 }
 
+ at test6_v1 = internal global { i32, i32 } { i32 42, i32 0 }, align 8
+ at test6_v2 = global i32 0, align 4
+; CHECK: @test6_v2 = global i32 42, align 4
+define internal void @test6() {
+  %load = load { i32, i32 }* @test6_v1, align 8
+  %xv0 = extractvalue { i32, i32 } %load, 0
+  %iv = insertvalue { i32, i32 } %load, i32 %xv0, 1
+  %xv1 = extractvalue { i32, i32 } %iv, 1
+  store i32 %xv1, i32* @test6_v2, align 4
+  ret void
+}
+
 @llvm.global_ctors = appending constant
-  [5 x { i32, void ()* }]
+  [6 x { i32, void ()* }]
   [{ i32, void ()* } { i32 65535, void ()* @test1 },
    { i32, void ()* } { i32 65535, void ()* @test2 },
    { i32, void ()* } { i32 65535, void ()* @test3 },
    { i32, void ()* } { i32 65535, void ()* @test4 },
-   { i32, void ()* } { i32 65535, void ()* @test5 }]
+   { i32, void ()* } { i32 65535, void ()* @test5 },
+   { i32, void ()* } { i32 65535, void ()* @test6 }]