MIPS64: Fix 'MIPS: use DAHI/DATH for li macro on mips64r6.'

src/mips64/macro-assembler-mips64.cc

Index: src/mips64/macro-assembler-mips64.cc
diff --git a/src/mips64/macro-assembler-mips64.cc b/src/mips64/macro-assembler-mips64.cc
index fcc602bbffd4a816b61cefd53e276090814b6e7c..96e42b36a69013fc67cc43def3d8b34bacfced0d 100644
--- a/src/mips64/macro-assembler-mips64.cc
+++ b/src/mips64/macro-assembler-mips64.cc
@@ -1378,15 +1378,9 @@ void MacroAssembler::li(Register rd, Operand j, LiFlags mode) {
     } else {
       if (kArchVariant == kMips64r6) {
         int64_t imm = j.imm64_;
-        bool lui_emited = false;
-        if (((imm >> kLuiShift) & kImm16Mask) != 0) {
-          lui(rd, (imm >> kLuiShift) & kImm16Mask);
-          lui_emited = true;
-        }
+        lui(rd, (imm >> kLuiShift) & kImm16Mask);
         if ((imm & kImm16Mask) != 0) {
           ori(rd, rd, (imm & kImm16Mask));
-        } else if (!lui_emited) {
-          or_(rd, zero_reg, zero_reg);
         }

[balazs.kilvady, 2016/02/23 19:56:23]

If I got it correctly at late evening then you use lui; ori for loading the
lower 32 bits of the imm. But if the
if (((imm >> kLuiShift) & kImm16Mask) == 0) then a
daddiu(rd, zero_reg, (j.imm64_ & kImm16Mask));
is quicker/smaller then a lui(rd, 0); ori(rd, rd, j.imm64_ & kImm16Mask);
Why don't you use the upper code block of if (is_int32(j.imm64_)) {} to load the
lower 32 bits? In that case that code could be put in a helper function to keep
the code DRY.

[Alan Li, 2016/02/25 03:05:40]

Done.

         if ((imm >> 31) & 0x1) {

[balazs.kilvady, 2016/02/23 19:56:23]

Don't we have kImm32Mask? If not yet then I think that should be added.

[Alan Li, 2016/02/25 03:05:39]

Consolidated into shiftAndFixSignExtension.

On 2016/02/23 19:56:23, balazs.kilvady wrote:

           imm = (imm >> 32) + 1;