From 22b34cce4d270f787d4c991baee596a9e3b7f836 Mon Sep 17 00:00:00 2001 From: Chad Rosier Date: Tue, 15 Nov 2011 23:34:05 +0000 Subject: [PATCH] GEPs with all zero indices are trivially coalesced by fast-isel. For example, %arrayidx135 = getelementptr inbounds [4 x [4 x [4 x [4 x i32]]]]* %M0, i32 0, i64 0 %arrayidx136 = getelementptr inbounds [4 x [4 x [4 x i32]]]* %arrayidx135, i32 0, i64 %idxprom134 Prior to this commit, the GEP instruction that defines %arrayidx136 thought that %arrayidx135 was a trivial kill. The GEP that defines %arrayidx135 doesn't generate any code and thus %M0 gets folded into the second GEP. Thus, we need to look through GEPs with all zero indices. rdar://10443319 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144730 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/FastISel.cpp | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp index e8f8c73d688..c58d730454f 100644 --- a/lib/CodeGen/SelectionDAG/FastISel.cpp +++ b/lib/CodeGen/SelectionDAG/FastISel.cpp @@ -96,6 +96,11 @@ bool FastISel::hasTrivialKill(const Value *V) const { !hasTrivialKill(Cast->getOperand(0))) return false; + // GEPs with all zero indices are trivially coalesced by fast-isel. + if (const GetElementPtrInst *GEP = dyn_cast(I)) + if (GEP->hasAllZeroIndices() && !hasTrivialKill(GEP->getOperand(0))) + return false; + // Only instructions with a single use in the same basic block are considered // to have trivial kills. return I->hasOneUse() && -- 2.34.1