MIPS64: Fix TruncatingDiv.

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 9aa75700cbfe10f934ac3cf2a398bd6a6650b67d..2d3241fb9eaee70a2c95b3faca6a75c50f77a0b6 100644
--- a/src/mips64/macro-assembler-mips64.cc
+++ b/src/mips64/macro-assembler-mips64.cc
@@ -6069,7 +6069,7 @@ void MacroAssembler::TruncatingDiv(Register result,
   DCHECK(!result.is(at));
   base::MagicNumbersForDivision<uint32_t> mag =

[dusmil.imgtec, 2014/10/08 09:56:40]

Can we instantiate template class with int32_t parameter here?
Will it cause to much trouble to change this?

[Sven Panne, 2014/10/08 10:44:13]

Nope, the template parameter *must* be unsigned, otherwise all this stuff is
wrong. With full C++11 support I would have added

   static_assert(std::is_unsigned<T>, "T must be unsigned");

to base::MagicNumbersForDivision, but we're not there yet, so there's only a
comment. Furthermore, we only have only instantiations for uint32_t and
uint64_t, so you would get a linker error reminding you of that fact. :-)

   base::SignedDivisionByConstant(static_cast<uint32_t>(divisor));
-  li(at, Operand(mag.multiplier));
+  li(at, Operand(static_cast<int32_t>(mag.multiplier)));
   Mulh(result, dividend, Operand(at));
   bool neg = (mag.multiplier & (static_cast<uint32_t>(1) << 31)) != 0;
   if (divisor > 0 && neg) {