On 08/26/2014 05:58 AM, Jiong Wang wrote: > On 22/08/14 23:05, Richard Henderson wrote: >> Don't continually re-read data from cfun->machine. >> >> * config/aarch64/aarch64.c (aarch64_expand_prologue): Load >> cfun->machine->frame.hard_fp_offset into a local variable. >> --- >> gcc/config/aarch64/aarch64.c | 14 +++++++------- >> 1 file changed, 7 insertions(+), 7 deletions(-) >> >> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c >> index dcca446..c890773 100644 >> --- a/gcc/config/aarch64/aarch64.c >> +++ b/gcc/config/aarch64/aarch64.c >> @@ -2194,18 +2194,18 @@ aarch64_expand_prologue (void) >> */ >> HOST_WIDE_INT frame_size, offset; >> HOST_WIDE_INT fp_offset; /* Offset from hard FP to SP. */ >> + HOST_WIDE_INT hard_fp_offset; >> rtx insn; >> aarch64_layout_frame (); >> - if (flag_stack_usage_info) >> - current_function_static_stack_size = cfun->machine->frame.frame_size; >> - >> frame_size = cfun->machine->frame.frame_size; >> - offset = cfun->machine->frame.frame_size; >> + hard_fp_offset = cfun->machine->frame.hard_fp_offset; >> + offset = frame_size; >> + fp_offset = frame_size - hard_fp_offset; > > there is a field "hardfp_offset" in aarch64_frame, and I think that field is > not used and not initialized correctly. > > how about hoisting the calculation to aarch64_layout_frame to avoid duplicated > calcuation here and there, something like: > > cfun->machine->frame.hardfp_offset = (cfun->machine->frame.frame_size- > cfun->machine->frame.hard_fp_offset); > > then use it directly in expand_epilogue: > > fp_offset = cfun->machine->frame.hardfp_offset;
I'd go the other way, and simply delete hardfp_offset as unused. We need the other two inputs to the subtraction for other reasons, so we don't save anything by pre-computing the subtract. r~
