Avoid unnecessary copy/load in EvalLoc() and LoadValue().

EvalLoc()/EvalLocWide() are used to prepare a register where
a value is subsequently stored, so they shouldn't copy the
old value to the new register for register class mismatch.

The only exception where we actually need a copy is
LoadValue()/LoadValueWide(), so we inline the old code that
makes the copy there. We also avoid loading inexpensive
constants when the value is already in the register.

Change-Id: I07519e9d4d9b3f7272233d196435f3035e4a3ca9

1 files changed, 2 insertions, 4 deletions

diff --git a/compiler/dex/quick/ralloc_util.cc b/compiler/dex/quick/ralloc_util.cc
index ca9a3ab64f..04de286ae2 100644
--- a/compiler/dex/quick/ralloc_util.cc
+++ b/compiler/dex/quick/ralloc_util.cc
@@ -937,9 +937,8 @@ RegLocation Mir2Lir::EvalLocWide(RegLocation loc, int reg_class, bool update) {
   /* If already in registers, we can assume proper form.  Right reg class? */
   if (loc.location == kLocPhysReg) {
     if (!RegClassMatches(reg_class, loc.reg)) {
-      /* Wrong register class.  Reallocate and copy */
+      // Wrong register class.  Reallocate and transfer ownership.
       RegStorage new_regs = AllocTypedTempWide(loc.fp, reg_class);
-      OpRegCopyWide(new_regs, loc.reg);
       // Associate the old sreg with the new register and clobber the old register.
       GetRegInfo(new_regs)->SetSReg(GetRegInfo(loc.reg)->SReg());
       Clobber(loc.reg);
@@ -971,9 +970,8 @@ RegLocation Mir2Lir::EvalLoc(RegLocation loc, int reg_class, bool update) {
 
   if (loc.location == kLocPhysReg) {
     if (!RegClassMatches(reg_class, loc.reg)) {
-      /* Wrong register class.  Realloc, copy and transfer ownership */
+      // Wrong register class.  Reallocate and transfer ownership.
       RegStorage new_reg = AllocTypedTemp(loc.fp, reg_class);
-      OpRegCopy(new_reg, loc.reg);
       // Associate the old sreg with the new register and clobber the old register.
       GetRegInfo(new_reg)->SetSReg(GetRegInfo(loc.reg)->SReg());
       Clobber(loc.reg);