commit 0dc242d6fc1254e6ca1c31e08e612bbf45644b17
author Vladimir Marko <vmarko@google.com> Mon May 12 16:22:14 2014 +0100
committer Vladimir Marko <vmarko@google.com> Mon May 12 16:48:58 2014 +0100
tree a3389b2a7642745cd71843e903a77ea4282be284
parent 6663c90d2f94b0035fabcaee1f26fd840c9f9161

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

compiler/dex/quick/gen_loadstore.cc

diff --git a/compiler/dex/quick/gen_loadstore.cc b/compiler/dex/quick/gen_loadstore.cc
index faa9461..8fcb09b 100644
--- a/compiler/dex/quick/gen_loadstore.cc
+++ b/compiler/dex/quick/gen_loadstore.cc
@@ -139,12 +139,25 @@
 }
 
 RegLocation Mir2Lir::LoadValue(RegLocation rl_src, RegisterClass op_kind) {
-  rl_src = EvalLoc(rl_src, op_kind, false);
-  if (IsInexpensiveConstant(rl_src) || rl_src.location != kLocPhysReg) {
-    LoadValueDirect(rl_src, rl_src.reg);
-    rl_src.location = kLocPhysReg;
-    MarkLive(rl_src);
+  rl_src = UpdateLoc(rl_src);
+  if (rl_src.location == kLocPhysReg) {
+    if (!RegClassMatches(op_kind, rl_src.reg)) {
+      // Wrong register class, realloc, copy and transfer ownership.
+      RegStorage new_reg = AllocTypedTemp(rl_src.fp, op_kind);
+      OpRegCopy(new_reg, rl_src.reg);
+      // Associate the old sreg with the new register and clobber the old register.
+      GetRegInfo(new_reg)->SetSReg(GetRegInfo(rl_src.reg)->SReg());
+      Clobber(rl_src.reg);
+      rl_src.reg = new_reg;
+    }
+    return rl_src;
   }
+
+  DCHECK_NE(rl_src.s_reg_low, INVALID_SREG);
+  rl_src.reg = AllocTypedTemp(rl_src.fp, op_kind);
+  LoadValueDirect(rl_src, rl_src.reg);
+  rl_src.location = kLocPhysReg;
+  MarkLive(rl_src);
   return rl_src;
 }
 
@@ -203,12 +216,26 @@
 
 RegLocation Mir2Lir::LoadValueWide(RegLocation rl_src, RegisterClass op_kind) {
   DCHECK(rl_src.wide);
-  rl_src = EvalLoc(rl_src, op_kind, false);
-  if (IsInexpensiveConstant(rl_src) || rl_src.location != kLocPhysReg) {
-    LoadValueDirectWide(rl_src, rl_src.reg);
-    rl_src.location = kLocPhysReg;
-    MarkLive(rl_src);
+  rl_src = UpdateLocWide(rl_src);
+  if (rl_src.location == kLocPhysReg) {
+    if (!RegClassMatches(op_kind, rl_src.reg)) {
+      // Wrong register class, realloc, copy and transfer ownership.
+      RegStorage new_regs = AllocTypedTempWide(rl_src.fp, op_kind);
+      OpRegCopyWide(new_regs, rl_src.reg);
+      // Associate the old sreg with the new register and clobber the old register.
+      GetRegInfo(new_regs)->SetSReg(GetRegInfo(rl_src.reg)->SReg());
+      Clobber(rl_src.reg);
+      rl_src.reg = new_regs;
+    }
+    return rl_src;
   }
+
+  DCHECK_NE(rl_src.s_reg_low, INVALID_SREG);
+  DCHECK_NE(GetSRegHi(rl_src.s_reg_low), INVALID_SREG);
+  rl_src.reg = AllocTypedTempWide(rl_src.fp, op_kind);
+  LoadValueDirectWide(rl_src, rl_src.reg);
+  rl_src.location = kLocPhysReg;
+  MarkLive(rl_src);
   return rl_src;
 }