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| author | Chad Rosier <mcrosier@apple.com> | 2011-11-15 23:34:05 +0000 |
|---|---|---|
| committer | Chad Rosier <mcrosier@apple.com> | 2011-11-15 23:34:05 +0000 |
| commit | 22b34cce4d270f787d4c991baee596a9e3b7f836 (patch) | |
| tree | 9ea1b16af909b16585be9b5062b81185a0d5bb1b /lib/CodeGen/SelectionDAG/FastISel.cpp | |
| parent | e43862b6a6130ec29ee4e9e6c6c30b5607c9a728 (diff) | |
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
Diffstat (limited to 'lib/CodeGen/SelectionDAG/FastISel.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/FastISel.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp index e8f8c73d68..c58d730454 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<GetElementPtrInst>(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() && |