Add a utility function to MachineInstr for testing whether an instruction

has exactly one MachineMemOperand, and change some X86 lowering code to
make use of it.

llvm-svn: 53498

2 files changed, 10 insertions, 7 deletions

diff --git a/llvm/include/llvm/CodeGen/MachineInstr.h b/llvm/include/llvm/CodeGen/MachineInstr.h
index 88116d2bb21..31f49746991 100644
--- a/llvm/include/llvm/CodeGen/MachineInstr.h
+++ b/llvm/include/llvm/CodeGen/MachineInstr.h
@@ -115,6 +115,13 @@ public:
   { return MemOperands.end(); }
   bool memoperands_empty() const { return MemOperands.empty(); }
 
+  /// hasOneMemOperand - Return true if this instruction has exactly one
+  /// MachineMemOperand.
+  bool hasOneMemOperand() const {
+    return !memoperands_empty() &&
+           next(memoperands_begin()) == memoperands_end();
+  }
+
   /// isIdenticalTo - Return true if this instruction is identical to (same
   /// opcode and same operands as) the specified instruction.
   bool isIdenticalTo(const MachineInstr *Other) const {
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index 7822ed7cb38..2f191ffa4b1 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -2030,14 +2030,10 @@ MachineInstr* X86InstrInfo::foldMemoryOperand(MachineFunction &MF,
   // Check switch flag 
   if (NoFusing) return NULL;
 
+  // Determine the alignment of the load.
   unsigned Alignment = 0;
-  for (alist<MachineMemOperand>::iterator i = LoadMI->memoperands_begin(),
-       e = LoadMI->memoperands_end(); i != e; ++i) {
-    const MachineMemOperand &MRO = *i;
-    unsigned Align = MRO.getAlignment();
-    if (Align > Alignment)
-      Alignment = Align;
-  }
+  if (LoadMI->hasOneMemOperand())
+    Alignment = LoadMI->memoperands_begin()->getAlignment();
 
   // FIXME: Move alignment requirement into tables?
   if (Alignment < 16) {