Do not speculatively execute an instruction by hoisting it to its predecessor BB if any of its operands are defined but not used in BB. The transformation will prevent the operand from being sunk into the use block.

llvm-svn: 52244

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/VMCore/Value.cpp b/llvm/lib/VMCore/Value.cpp
index 919f4b00e87..e581fe83807 100644
--- a/llvm/lib/VMCore/Value.cpp
+++ b/llvm/lib/VMCore/Value.cpp
@@ -93,6 +93,17 @@ bool Value::hasNUsesOrMore(unsigned N) const {
   return true;
 }
 
+/// isUsedInBasicBlock - Return true if this value is used in the specified
+/// basic block.
+bool Value::isUsedInBasicBlock(BasicBlock *BB) const {
+  for (use_const_iterator I = use_begin(), E = use_end(); I != E; ++I) {
+    const Instruction *User = dyn_cast<Instruction>(*I);
+    if (User && User->getParent() == BB)
+      return true;
+  }
+  return false;
+}
+
 
 /// getNumUses - This method computes the number of uses of this Value.  This
 /// is a linear time operation.  Use hasOneUse or hasNUses to check for specific