Add a target hook to allow loads from constant pools to be rematerialized, and an

implementation for x86.

llvm-svn: 37576

2 files changed, 6 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
index eadd47b009b..aae27bb882d 100644
--- a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -336,12 +336,14 @@ void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
   // time we see a vreg.
   if (interval.empty()) {
     // Remember if the definition can be rematerialized. All load's from fixed
-    // stack slots are re-materializable.
+    // stack slots are re-materializable. The target may permit other loads to
+    // be re-materialized as well.
     int FrameIdx = 0;
     if (vi.DefInst &&
         (tii_->isReMaterializable(vi.DefInst->getOpcode()) ||
          (tii_->isLoadFromStackSlot(vi.DefInst, FrameIdx) &&
-          mf_->getFrameInfo()->isFixedObjectIndex(FrameIdx))))
+          mf_->getFrameInfo()->isFixedObjectIndex(FrameIdx)) ||
+         tii_->isOtherReMaterializableLoad(vi.DefInst)))
       interval.remat = vi.DefInst;
 
     // Get the Idx of the defining instructions.
diff --git a/llvm/lib/CodeGen/VirtRegMap.cpp b/llvm/lib/CodeGen/VirtRegMap.cpp
index 9ae38ac9013..95453b0e3d5 100644
--- a/llvm/lib/CodeGen/VirtRegMap.cpp
+++ b/llvm/lib/CodeGen/VirtRegMap.cpp
@@ -664,7 +664,8 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM,
     // If this instruction is being rematerialized, just remove it!
     int FrameIdx;
     if ((TID->Flags & M_REMATERIALIZIBLE) ||
-        TII->isLoadFromStackSlot(&MI, FrameIdx)) {
+        TII->isLoadFromStackSlot(&MI, FrameIdx) ||
+        TII->isOtherReMaterializableLoad(&MI)) {
       bool Remove = true;
       for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
         MachineOperand &MO = MI.getOperand(i);