commit f793de7a2331edea161eae20f9bdfa86b0d7fd3c
author Lang Hames <lhames@gmail.com> Sat Mar 09 22:56:09 2013 +0000
committer Lang Hames <lhames@gmail.com> Sat Mar 09 22:56:09 2013 +0000
tree dcab834f7e88339434a2433b4bf496e96cf6cba9
parent d683edc711ec2ff4eb035ad56e07799b7da52b36

Don't glue users to extract_subreg when selecting the llvm.arm.ldrexd
intrinsic - it can cause impossible-to-schedule subgraphs to be
introduced.

PR15053.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176777 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMISelDAGToDAG.cpp

diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 5d9d784..2c51de2 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -3155,7 +3155,7 @@
       cast<MachineSDNode>(Ld)->setMemRefs(MemOp, MemOp + 1);
 
       // Remap uses.
-      SDValue Glue = isThumb ? SDValue(Ld, 2) : SDValue(Ld, 1);
+      SDValue OutChain = isThumb ? SDValue(Ld, 2) : SDValue(Ld, 1);
       if (!SDValue(N, 0).use_empty()) {
         SDValue Result;
         if (isThumb)
@@ -3163,9 +3163,8 @@
         else {
           SDValue SubRegIdx = CurDAG->getTargetConstant(ARM::gsub_0, MVT::i32);
           SDNode *ResNode = CurDAG->getMachineNode(TargetOpcode::EXTRACT_SUBREG,
-              dl, MVT::i32, MVT::Glue, SDValue(Ld, 0), SubRegIdx, Glue);
+              dl, MVT::i32, SDValue(Ld, 0), SubRegIdx);
           Result = SDValue(ResNode,0);
-          Glue = Result.getValue(1);
         }
         ReplaceUses(SDValue(N, 0), Result);
       }
@@ -3176,13 +3175,12 @@
         else {
           SDValue SubRegIdx = CurDAG->getTargetConstant(ARM::gsub_1, MVT::i32);
           SDNode *ResNode = CurDAG->getMachineNode(TargetOpcode::EXTRACT_SUBREG,
-              dl, MVT::i32, MVT::Glue, SDValue(Ld, 0), SubRegIdx, Glue);
+              dl, MVT::i32, SDValue(Ld, 0), SubRegIdx);
           Result = SDValue(ResNode,0);
-          Glue = Result.getValue(1);
         }
         ReplaceUses(SDValue(N, 1), Result);
       }
-      ReplaceUses(SDValue(N, 2), Glue);
+      ReplaceUses(SDValue(N, 2), OutChain);
       return NULL;
     }
 

test/CodeGen/ARM/2013-03-09-PR15053.ll

diff --git a/test/CodeGen/ARM/2013-03-09-PR15053.ll b/test/CodeGen/ARM/2013-03-09-PR15053.ll
new file mode 100644
index 0000000..706a90e
--- /dev/null
+++ b/test/CodeGen/ARM/2013-03-09-PR15053.ll
@@ -0,0 +1,13 @@
+; RUN: llc -mtriple=armv7 < %s
+; PR15053
+
+declare i32 @llvm.arm.strexd(i32, i32, i8*) nounwind
+declare { i32, i32 } @llvm.arm.ldrexd(i8*) nounwind readonly
+
+define void @foo() {
+entry:
+  %0 = tail call { i32, i32 } @llvm.arm.ldrexd(i8* undef) nounwind
+  %1 = extractvalue { i32, i32 } %0, 0
+  %2 = tail call i32 @llvm.arm.strexd(i32 %1, i32 undef, i8* undef) nounwind
+  ret void
+}