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authorBjörn Gustavsson <[email protected]>2012-04-10 12:28:11 +0200
committerBjörn Gustavsson <[email protected]>2015-07-03 14:34:58 +0200
commitd252130b8e880f2f7f826217fe806da76fbcbb7c (patch)
tree6635b56c7e25ac77ca44fa70703627a2fbfe6c07 /erts/emulator/beam/erl_unicode.c
parentdddd225934cfe79c052e9013a8a2c1d6a29c8ae0 (diff)
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Rewrite the hipe_mode_switch instructions
The 'cmd' variable that were shared by several hipe_mode_switch instructions would cause clang to produce sub-optimal code, probably because it considered the instructions as part of of loop that needed to be optimized. What would was that 'cmd' would be assigned to the ESI register (lower 32 bits of the RSI register). It would use ESI for other purposes in instructions, but at the end of every instruction it would set ESI to 1 just in case the next instruction happened to be hipe_trap_return. This can be seen clearly if this commit is omitted and the define HIPE_MODE_SWITCH_CMD_RETURN in hipe/hipe_mode_switch.h is changed from 1 to some other number such as 42. You will see that 42 is assigned to ESI at the end of every instruction. Eliminate this problem by elimininating the shared 'cmd' variable.
Diffstat (limited to 'erts/emulator/beam/erl_unicode.c')
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