diff options
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/config/i386/i386.c | 14 |
2 files changed, 18 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index e34536b..f6ef56a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +Thu Sep 30 18:34:54 1999 Jan Hubicka <hubicka@freesoft.cz> + + * i386.c (ix86_adjust_cost): Ignore false ebp dependencies in + prologues. + Thu Sep 30 18:31:36 1999 Jan Hubicka <hubicka@freesoft.cz> * alias.c: Include insn-flags.h. diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 34a68a7..69b1170 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -5325,15 +5325,27 @@ ix86_adjust_cost (insn, link, dep_insn, cost) { enum attr_type insn_type, dep_insn_type; rtx set, set2; + int dep_insn_code_number; /* We describe no anti or output depenancies. */ if (REG_NOTE_KIND (link) != 0) return cost; + dep_insn_code_number = recog_memoized (dep_insn); + /* If we can't recognize the insns, we can't really do anything. */ - if (recog_memoized (insn) < 0 || recog_memoized (dep_insn) < 0) + if (dep_insn_code_number < 0 || recog_memoized (insn) < 0) return cost; + /* Prologue and epilogue allocators have false dependency on ebp. + This results in one cycle extra stall on Pentium prologue scheduling, so + handle this important case manually. */ + + if ((dep_insn_code_number == CODE_FOR_prologue_allocate_stack + || dep_insn_code_number == CODE_FOR_epilogue_deallocate_stack) + && !reg_mentioned_p (stack_pointer_rtx, insn)) + return 0; + insn_type = get_attr_type (insn); dep_insn_type = get_attr_type (dep_insn); |