MIPS: Fixing illegal use of at register

src/compiler/mips/code-generator-mips.cc

Index: src/compiler/mips/code-generator-mips.cc
diff --git a/src/compiler/mips/code-generator-mips.cc b/src/compiler/mips/code-generator-mips.cc
index cdd8bdb337199456955860b100df294902cdc996..29c0892c1fe4568f975a32b325dd6e0ebcd0de11 100644
--- a/src/compiler/mips/code-generator-mips.cc
+++ b/src/compiler/mips/code-generator-mips.cc
@@ -304,8 +304,8 @@ FPUCondition FlagsConditionToConditionCmpFPU(bool& predicate,
     if (instr->InputAt(0)->IsRegister()) {                                    \
       auto offset = i.InputRegister(0);                                       \
       __ Branch(USE_DELAY_SLOT, ool->entry(), hs, offset, i.InputOperand(1)); \
-      __ addu(at, i.InputRegister(2), offset);                                \
-      __ asm_instr(result, MemOperand(at, 0));                                \
+      __ addu(t8, i.InputRegister(2), offset);                                \
+      __ asm_instr(result, MemOperand(t8, 0));                                \

[paul.l..., 2015/08/31 22:56:34]

I think these temp regs should be kScratchReg or possibly kScratchReg2. t8 is
reserved for macro-assembler, and we should probably preserve that layering.

Also note that Assembler::sdc1() now uses t8 as a 2nd temporary. I think that
usage would still work, since we would only overwrite t8 after we have the
address, but it seems a bit fragile.

[Djordje.Pesic, 2015/09/07 11:34:17]

Done.

     } else {                                                                  \
       auto offset = i.InputOperand(0).immediate();                            \
       __ Branch(ool->entry(), ls, i.InputRegister(1), Operand(offset));       \
@@ -322,8 +322,8 @@ FPUCondition FlagsConditionToConditionCmpFPU(bool& predicate,
     if (instr->InputAt(0)->IsRegister()) {                                    \
       auto offset = i.InputRegister(0);                                       \
       __ Branch(USE_DELAY_SLOT, ool->entry(), hs, offset, i.InputOperand(1)); \
-      __ addu(at, i.InputRegister(2), offset);                                \
-      __ asm_instr(result, MemOperand(at, 0));                                \
+      __ addu(t8, i.InputRegister(2), offset);                                \
+      __ asm_instr(result, MemOperand(t8, 0));                                \
     } else {                                                                  \
       auto offset = i.InputOperand(0).immediate();                            \
       __ Branch(ool->entry(), ls, i.InputRegister(1), Operand(offset));       \
@@ -340,8 +340,8 @@ FPUCondition FlagsConditionToConditionCmpFPU(bool& predicate,
       auto offset = i.InputRegister(0);                                \
       auto value = i.Input##width##Register(2);                        \
       __ Branch(USE_DELAY_SLOT, &done, hs, offset, i.InputOperand(1)); \
-      __ addu(at, i.InputRegister(3), offset);                         \
-      __ asm_instr(value, MemOperand(at, 0));                          \
+      __ addu(t8, i.InputRegister(3), offset);                         \
+      __ asm_instr(value, MemOperand(t8, 0));                          \
     } else {                                                           \
       auto offset = i.InputOperand(0).immediate();                     \
       auto value = i.Input##width##Register(2);                        \
@@ -359,8 +359,8 @@ FPUCondition FlagsConditionToConditionCmpFPU(bool& predicate,
       auto offset = i.InputRegister(0);                                \
       auto value = i.InputRegister(2);                                 \
       __ Branch(USE_DELAY_SLOT, &done, hs, offset, i.InputOperand(1)); \
-      __ addu(at, i.InputRegister(3), offset);                         \
-      __ asm_instr(value, MemOperand(at, 0));                          \
+      __ addu(t8, i.InputRegister(3), offset);                         \
+      __ asm_instr(value, MemOperand(t8, 0));                          \
     } else {                                                           \
       auto offset = i.InputOperand(0).immediate();                     \
       auto value = i.InputRegister(2);                                 \