Place the lowered phi instruction(s) before the DEBUG_VALUE entry

When a phi node is finally lowered to a machine instruction it is
important that the lowered "load" instruction is placed before the
associated DEBUG_VALUE entry describing the value loaded.

Renamed the existing SkipPHIsAndLabels to SkipPHIsLabelsAndDebug to
more fully describe that it also skips debug entries. Then used the
"new" function SkipPHIsAndLabels when the debug information should not
be skipped when placing the lowered "load" instructions so that it is
placed before the debug entries.

Differential Revision: https://reviews.llvm.org/D23760 

llvm-svn: 281727

1 files changed, 14 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp
index b43a253e2df..55138f64198 100644
--- a/llvm/lib/CodeGen/MachineBasicBlock.cpp
+++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp
@@ -149,12 +149,25 @@ MachineBasicBlock::iterator MachineBasicBlock::getFirstNonPHI() {
 MachineBasicBlock::iterator
 MachineBasicBlock::SkipPHIsAndLabels(MachineBasicBlock::iterator I) {
   iterator E = end();
+  while (I != E && (I->isPHI() || I->isPosition()))
+    ++I;
+  // FIXME: This needs to change if we wish to bundle labels
+  // inside the bundle.
+  assert((I == E || !I->isInsideBundle()) &&
+         "First non-phi / non-label instruction is inside a bundle!");
+  return I;
+}
+
+MachineBasicBlock::iterator
+MachineBasicBlock::SkipPHIsLabelsAndDebug(MachineBasicBlock::iterator I) {
+  iterator E = end();
   while (I != E && (I->isPHI() || I->isPosition() || I->isDebugValue()))
     ++I;
   // FIXME: This needs to change if we wish to bundle labels / dbg_values
   // inside the bundle.
   assert((I == E || !I->isInsideBundle()) &&
-         "First non-phi / non-label instruction is inside a bundle!");
+         "First non-phi / non-label / non-debug "
+         "instruction is inside a bundle!");
   return I;
 }