xmm0 is not saved across runtime call on x64 because MacroAssembler::EnterExitFrameEpilogue preserves only allocatable XMM registers unlike on ia32 where it preserves all registers.
Cleanup handling of shifts: SHR can deoptimize only when its a shift by 0, all other shift never deoptimize.
Fix type inference for i-to-t change instruction. On X64 this ensures that write-barrier is generated correctly.
R=danno@chromium.org
Review URL: https://chromiumcodereview.appspot.com/10868032
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12373 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Safe operations are those that either do not observe unsignedness or have special support for uint32 values:
- all binary bitwise operations: they perform ToInt32 on inputs;
- >> and << shifts: they perform ToInt32 on left hand side and ToUint32 on right hand side;
- >>> shift: it performs ToUint32 on both inputs;
- stores to integer external arrays (not pixel, float or double ones): these stores are "bitwise";
- HChange: special support added for conversions of uint32 values to double and tagged values;
- HSimulate: special support added for deoptimization with uint32 values in registers and stack slots;
- HPhi: phis that have only safe uses and only uint32 operands are uint32 themselves.
BUG=v8:2097
TEST=test/mjsunit/compiler/uint32.js
Review URL: https://chromiumcodereview.appspot.com/10778029
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12367 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
