Slightly change the meaning of the reMaterialize target hook when the original

instruction defines subregisters.

Any existing subreg indices on the original instruction are preserved or
composed with the new subreg index.

Also substitute multiple operands mentioning the original register by using the
new MachineInstr::substituteRegister() function. This is necessary because there
will soon be <imp-def> operands added to non read-modify-write partial
definitions. This instruction:

  %reg1234:foo = FLAP %reg1234<imp-def>

will reMaterialize(%reg3333, bar) like this:

  %reg3333:bar-foo = FLAP %reg333:bar<imp-def>

Finally, replace the TargetRegisterInfo pointer argument with a reference to
indicate that it cannot be NULL.

llvm-svn: 105358

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 402178dc6d6..7e60c3215d3 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -1037,6 +1037,29 @@ void MachineInstr::copyPredicates(const MachineInstr *MI) {
   }
 }
 
+void MachineInstr::substituteRegister(unsigned FromReg,
+                                      unsigned ToReg,
+                                      unsigned SubIdx,
+                                      const TargetRegisterInfo &RegInfo) {
+  if (TargetRegisterInfo::isPhysicalRegister(ToReg)) {
+    if (SubIdx)
+      ToReg = RegInfo.getSubReg(ToReg, SubIdx);
+    for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+      MachineOperand &MO = getOperand(i);
+      if (!MO.isReg() || MO.getReg() != FromReg)
+        continue;
+      MO.substPhysReg(ToReg, RegInfo);
+    }
+  } else {
+    for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+      MachineOperand &MO = getOperand(i);
+      if (!MO.isReg() || MO.getReg() != FromReg)
+        continue;
+      MO.substVirtReg(ToReg, SubIdx, RegInfo);
+    }
+  }
+}
+
 /// isSafeToMove - Return true if it is safe to move this instruction. If
 /// SawStore is set to true, it means that there is a store (or call) between
 /// the instruction's location and its intended destination.