diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/gcse.c | 52 |
2 files changed, 56 insertions, 2 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9f895084..8898bea 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2003-02-07 Richard Henderson <rth@redhat.com> + + PR 9226 + * gcse.c (local_cprop_find_used_regs): New. + (local_cprop_pass): Use it. + 2003-02-07 Fred Fish <fnf@intrinsity.com> * mips-tfile.c (parse_def): Parenthesize assignments to fix @@ -706,6 +706,7 @@ static void free_insn_expr_list_list PARAMS ((rtx *)); static void clear_modify_mem_tables PARAMS ((void)); static void free_modify_mem_tables PARAMS ((void)); static rtx gcse_emit_move_after PARAMS ((rtx, rtx, rtx)); +static void local_cprop_find_used_regs PARAMS ((rtx *, void *)); static bool do_local_cprop PARAMS ((rtx, rtx, int, rtx*)); static bool adjust_libcall_notes PARAMS ((rtx, rtx, rtx, rtx*)); static void local_cprop_pass PARAMS ((int)); @@ -4258,6 +4259,53 @@ cprop_insn (insn, alter_jumps) return changed; } +/* Like find_used_regs, but avoid recording uses that appear in + input-output contexts such as zero_extract or pre_dec. This + restricts the cases we consider to those for which local cprop + can legitimately make replacements. */ + +static void +local_cprop_find_used_regs (xptr, data) + rtx *xptr; + void *data; +{ + rtx x = *xptr; + + if (x == 0) + return; + + switch (GET_CODE (x)) + { + case ZERO_EXTRACT: + case SIGN_EXTRACT: + case STRICT_LOW_PART: + return; + + case PRE_DEC: + case PRE_INC: + case POST_DEC: + case POST_INC: + case PRE_MODIFY: + case POST_MODIFY: + /* Can only legitimately appear this early in the context of + stack pushes for function arguments, but handle all of the + codes nonetheless. */ + return; + + case SUBREG: + /* Setting a subreg of a register larger than word_mode leaves + the non-written words unchanged. */ + if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) > BITS_PER_WORD) + return; + break; + + default: + break; + } + + find_used_regs (xptr, data); +} + /* LIBCALL_SP is a zero-terminated array of insns at the end of a libcall; their REG_EQUAL notes need updating. */ @@ -4413,9 +4461,9 @@ local_cprop_pass (alter_jumps) do { reg_use_count = 0; - note_uses (&PATTERN (insn), find_used_regs, NULL); + note_uses (&PATTERN (insn), local_cprop_find_used_regs, NULL); if (note) - find_used_regs (&XEXP (note, 0), NULL); + local_cprop_find_used_regs (&XEXP (note, 0), NULL); for (reg_used = ®_use_table[0]; reg_use_count > 0; reg_used++, reg_use_count--) |