Teach the inline spiller to attempt folding a load instruction into its single

use before rematerializing the load.

This allows us to produce:

    addps	LCPI0_1(%rip), %xmm2

Instead of:

    movaps	LCPI0_1(%rip), %xmm3
    addps	%xmm3, %xmm2

Saving a register and an instruction. The standard spiller already knows how to
do this.

llvm-svn: 122133

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/LiveRangeEdit.h b/llvm/lib/CodeGen/LiveRangeEdit.h
index ad248bf4002..37b58279b1b 100644
--- a/llvm/lib/CodeGen/LiveRangeEdit.h
+++ b/llvm/lib/CodeGen/LiveRangeEdit.h
@@ -117,6 +117,12 @@ public:
                             const TargetInstrInfo&,
                             const TargetRegisterInfo&);
 
+  /// markRematerialized - explicitly mark a value as rematerialized after doing
+  /// it manually.
+  void markRematerialized(VNInfo *ParentVNI) {
+    rematted_.insert(ParentVNI);
+  }
+
   /// didRematerialize - Return true if ParentVNI was rematerialized anywhere.
   bool didRematerialize(VNInfo *ParentVNI) const {
     return rematted_.count(ParentVNI);