From adeb0a6e64c5a63e891e016226645f9595d00959 Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Thu, 15 Dec 2011 04:33:48 +0000
Subject: [PATCH] Make constant folding for GEPs a bit more aggressive.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146639 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/VMCore/ConstantFold.cpp | 2 +-
test/Other/constant-fold-gep.ll | 7 +++++--
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 30bae7162ce..d1a9e7a70f9 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -2209,7 +2209,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
I != E; ++I)
LastTy = *I;
- if ((LastTy && LastTy->isArrayTy()) || Idx0->isNullValue()) {
+ if ((LastTy && isa<SequentialType>(LastTy)) || Idx0->isNullValue()) {
SmallVector<Value*, 16> NewIndices;
NewIndices.reserve(Idxs.size() + CE->getNumOperands());
for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
diff --git a/test/Other/constant-fold-gep.ll b/test/Other/constant-fold-gep.ll
index e4521d5184a..79ddaf2d12a 100644
--- a/test/Other/constant-fold-gep.ll
+++ b/test/Other/constant-fold-gep.ll
@@ -102,14 +102,17 @@
@N = constant i64* getelementptr ({ i64, i64 }* null, i32 0, i32 1)
@O = constant i64* getelementptr ([2 x i64]* null, i32 0, i32 1)
-; Fold GEP of a GEP. Theoretically some of these cases could be folded
-; without using targetdata, however that's not implemented yet.
+; Fold GEP of a GEP. Very simple cases are folded without targetdata.
+; PLAIN: @Y = global [3 x { i32, i32 }]* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 2)
; PLAIN: @Z = global i32* getelementptr inbounds (i32* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 0), i64 1)
+; OPT: @Y = global [3 x { i32, i32 }]* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 2)
; OPT: @Z = global i32* getelementptr (i32* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 0), i64 1)
+; TO: @Y = global [3 x { i32, i32 }]* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 2)
; TO: @Z = global i32* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 1)
@ext = external global [3 x { i32, i32 }]
+@Y = global [3 x { i32, i32 }]* getelementptr inbounds ([3 x { i32, i32 }]* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 1), i64 1)
@Z = global i32* getelementptr inbounds (i32* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 0), i64 1)
; Duplicate all of the above as function return values rather than