[PATCH] D31668: Fix PR30562
Dinar Temirbulatov via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Apr 6 22:51:42 PDT 2017
dtemirbulatov updated this revision to Diff 94482.
dtemirbulatov added a comment.
here we are checking that the store depends on the extractelement operation.
https://reviews.llvm.org/D31668
Files:
lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
test/CodeGen/X86/pr30562.ll
Index: test/CodeGen/X86/pr30562.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/pr30562.ll
@@ -0,0 +1,22 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s
+
+define i32 @foo(i64* nocapture %perm, i32 %n) {
+entry:
+ br label %body
+
+body:
+; CHECK-LABEL: foo:
+; CHECK: pslldq $8, %xmm0
+ %vec.ind = phi <2 x i64> [ <i64 0, i64 1>, %entry ], [ <i64 2, i64 3>, %body ]
+ %l13 = extractelement <2 x i64> %vec.ind, i32 %n
+ %l14 = getelementptr inbounds i64, i64* %perm, i64 %l13
+ %l15 = bitcast i64* %l14 to <2 x i64>*
+ store <2 x i64> %vec.ind, <2 x i64>* %l15, align 8
+ %niter.ncmp.3 = icmp eq i64 %l13, 0
+ br i1 %niter.ncmp.3, label %exit, label %body
+
+exit:
+ ret i32 %n
+
+}
+
Index: lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1192,8 +1192,11 @@
// If the index is dependent on the store we will introduce a cycle when
// creating the load (the load uses the index, and by replacing the chain
- // we will make the index dependent on the load).
- if (SDNode::hasPredecessorHelper(ST, Visited, Worklist))
+ // we will make the index dependent on the load). Also, the store might be
+ // dependent on the extractelement and introduce a cycle when creating
+ // the load.
+ if (SDNode::hasPredecessorHelper(ST, Visited, Worklist) ||
+ ST->hasPredecessor(Op.getNode()))
continue;
StackPtr = ST->getBasePtr();
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