diff options
Diffstat (limited to 'gcc/implicit-zee.c')
| -rw-r--r-- | gcc/implicit-zee.c | 166 |
1 files changed, 80 insertions, 86 deletions
diff --git a/gcc/implicit-zee.c b/gcc/implicit-zee.c index 46029cdac38..e2716d305a7 100644 --- a/gcc/implicit-zee.c +++ b/gcc/implicit-zee.c @@ -100,17 +100,17 @@ along with GCC; see the file COPYING3. If not see } ********************************************** - $ gcc -O2 -fsee bad_code.c (Turned on existing sign-extension elimination.) + $ gcc -O2 -fsee bad_code.c (Turned on existing sign-extension elimination) ........ 400315: b8 4e 00 00 00 mov $0x4e,%eax 40031a: 0f af f8 imul %eax,%edi - 40031d: 89 ff mov %edi,%edi ---> Useless extend. + 40031d: 89 ff mov %edi,%edi --> Useless extend 40031f: 8b 04 bd 60 19 40 00 mov 0x401960(,%rdi,4),%eax 400326: c3 retq ...... 400330: ba 2d 00 00 00 mov $0x2d,%edx 400335: 0f af fa imul %edx,%edi - 400338: 89 ff mov %edi,%edi ---> Useless extend. + 400338: 89 ff mov %edi,%edi --> Useless extend 40033a: 8b 04 bd 60 19 40 00 mov 0x401960(,%rdi,4),%eax 400341: c3 retq @@ -141,14 +141,14 @@ along with GCC; see the file COPYING3. If not see return (unsigned long long)(z); } - $ gcc -O2 -fsee bad_code.c (Turned on existing sign-extension elimination.) + $ gcc -O2 -fsee bad_code.c (Turned on existing sign-extension elimination) ............ 400360: 8d 14 3e lea (%rsi,%rdi,1),%edx 400363: 89 f8 mov %edi,%eax 400365: 29 f0 sub %esi,%eax 400367: 83 ff 65 cmp $0x65,%edi 40036a: 0f 43 c2 cmovae %edx,%eax - 40036d: 89 c0 mov %eax,%eax ---> Useless extend. + 40036d: 89 c0 mov %eax,%eax --> Useless extend 40036f: c3 retq $ gcc -O2 -fzee bad_code.c @@ -165,16 +165,13 @@ along with GCC; see the file COPYING3. If not see Usefulness : ---------- - This pass reduces the dynamic instruction count of a compression benchmark by - 2.8% and improves its run-time by about 1%. The compression benchmark had the - following code sequence in a very hot region of code before ZEE optimized it : + This pass reduces the dynamic instruction count of a compression benchmark + by 2.8% and improves its run time by about 1%. The compression benchmark + had the following code sequence in a very hot region of code before ZEE + optimized it : shr $0x5, %edx - mov %edx, %edx --> Useless zero-extend. - - How to turn on ? - ---------------- - -fzee -O2. */ + mov %edx, %edx --> Useless zero-extend */ #include "config.h" @@ -193,6 +190,7 @@ along with GCC; see the file COPYING3. If not see #include "expr.h" #include "insn-attr.h" #include "recog.h" +#include "diagnostic-core.h" #include "toplev.h" #include "target.h" #include "timevar.h" @@ -240,31 +238,6 @@ set_insn_status (rtx insn, enum insn_merge_code code) is_insn_merge_attempted[INSN_UID (insn)] = code; } -/* Check to see if this zero-extend matches a pattern - that could be eliminated. This is called via - for_each_rtx in function find_and_remove_ze. */ - -static int -is_set_with_extension_DI (rtx *expr, void *data) -{ - /* Looking only for patterns of the type : - SET (REG:DI X) (ZERO_EXTEND (REG:SI x)) - */ - - if (GET_CODE (*expr) == SET - && GET_MODE (SET_DEST (*expr)) == DImode - && GET_CODE (SET_DEST (*expr)) == REG - && GET_CODE (SET_SRC (*expr)) == ZERO_EXTEND - && GET_CODE (XEXP (SET_SRC (*expr),0)) == REG - && GET_MODE (XEXP (SET_SRC (*expr),0)) == SImode - && REGNO (SET_DEST (*expr)) == REGNO (XEXP (SET_SRC (*expr),0))) - { - *(rtx **)(data) = expr; - return 1; - } - return 0; -} - /* Given a insn (CURR_INSN) and a pointer to the SET rtx (ORIG_SET) that needs to be modified, this code modifies the SET rtx to a new SET rtx that zero_extends the right hand expression into a DImode @@ -737,7 +710,7 @@ combine_reaching_defs (rtx zero_extend_insn, rtx set_pat) VEC_free (rtx, heap, defs_list); VEC_free (rtx, heap, copies_list); if (dump_file) - fprintf (dump_file, "All definitions have been merged previously...\n"); + fprintf (dump_file, "All definitions have been merged previously.\n"); return true; } @@ -812,8 +785,8 @@ combine_reaching_defs (rtx zero_extend_insn, rtx set_pat) } else { - /* Changes need not be cancelled explicitly as apply_change_group () - does it. Print list of definitions in the dump_file for debug + /* Changes need not be cancelled explicitly as apply_change_group + does it. Print list of definitions in the dump_file for debug purposes. This zero-extension cannot be deleted. */ if (dump_file) @@ -838,50 +811,74 @@ combine_reaching_defs (rtx zero_extend_insn, rtx set_pat) return false; } -/* Goes through the instruction stream looking for zero-extends. If the zero - extension instruction has atleast one def it adds it to a list of possible - candidates for deletion. It returns the list of candidates. */ +/* Carry information about zero-extensions while walking the RTL. */ + +struct zero_extend_info +{ + /* The insn where the zero-extension is. */ + rtx insn; + + /* The list of candidates. */ + VEC (rtx, heap) *insn_list; +}; + +/* Add a zero-extend pattern that could be eliminated. This is called via + note_stores from find_removable_zero_extends. */ + +static void +add_removable_zero_extend (rtx x ATTRIBUTE_UNUSED, const_rtx expr, void *data) +{ + struct zero_extend_info *zei = (struct zero_extend_info *)data; + rtx src, dest; + + /* We are looking for SET (REG:DI N) (ZERO_EXTEND (REG:SI N)). */ + if (GET_CODE (expr) != SET) + return; + + src = SET_SRC (expr); + dest = SET_DEST (expr); + + if (REG_P (dest) + && GET_MODE (dest) == DImode + && GET_CODE (src) == ZERO_EXTEND + && REG_P (XEXP (src, 0)) + && GET_MODE (XEXP (src, 0)) == SImode + && REGNO (dest) == REGNO (XEXP (src, 0))) + { + if (get_defs (zei->insn, XEXP (src, 0), NULL)) + VEC_safe_push (rtx, heap, zei->insn_list, zei->insn); + else if (dump_file) + { + fprintf (dump_file, "Cannot eliminate zero-extension: \n"); + print_rtl_single (dump_file, zei->insn); + fprintf (dump_file, "No defs. Could be extending parameters.\n"); + } + } +} + +/* Traverse the instruction stream looking for zero-extends and return the + list of candidates. */ static VEC (rtx,heap)* find_removable_zero_extends (void) { - VEC (rtx, heap) *zeinsn_list; - basic_block curr_block; - rtx curr_insn; - rtx *set_insn; - rtx which_reg; - int type ; - int has_defs; - - zeinsn_list = VEC_alloc (rtx, heap, 8); - FOR_EACH_BB (curr_block) - { - FOR_BB_INSNS (curr_block, curr_insn) - { - if (!NONDEBUG_INSN_P (curr_insn)) - continue; + struct zero_extend_info zei; + basic_block bb; + rtx insn; - type = for_each_rtx (&PATTERN (curr_insn), - is_set_with_extension_DI, - (void *)&set_insn); + zei.insn_list = VEC_alloc (rtx, heap, 8); - if (!type) - continue; + FOR_EACH_BB (bb) + FOR_BB_INSNS (bb, insn) + { + if (!NONDEBUG_INSN_P (insn)) + continue; - which_reg = XEXP (SET_SRC (*set_insn), 0); - has_defs = get_defs (curr_insn, which_reg, NULL); - if (has_defs) - VEC_safe_push (rtx, heap, zeinsn_list, curr_insn); - else if (dump_file) - { - fprintf (dump_file, "Cannot eliminate zero extension : \n"); - print_rtl_single (dump_file, curr_insn); - fprintf (dump_file, - "This has no defs. Could be extending parameters.\n"); - } - } - } - return zeinsn_list; + zei.insn = insn; + note_stores (PATTERN (insn), add_removable_zero_extend, &zei); + } + + return zei.insn_list; } /* This is the main function that checks the insn stream for redundant @@ -906,13 +903,12 @@ find_and_remove_ze (void) max_insn_uid = get_max_uid (); - is_insn_merge_attempted = XNEWVEC (enum insn_merge_code, - sizeof (enum insn_merge_code)* max_insn_uid); + is_insn_merge_attempted + = XNEWVEC (enum insn_merge_code, + sizeof (enum insn_merge_code) * max_insn_uid); for (i = 0; i < max_insn_uid; i++) - { - is_insn_merge_attempted[i] = MERGE_NOT_ATTEMPTED; - } + is_insn_merge_attempted[i] = MERGE_NOT_ATTEMPTED; num_ze_opportunities = num_realized = 0; @@ -942,9 +938,7 @@ find_and_remove_ze (void) /* Delete all useless zero extensions here in one sweep. */ for (ix = 0; VEC_iterate (rtx, zeinsn_del_list, ix, curr_insn); ix++) - { - delete_insn (curr_insn); - } + delete_insn (curr_insn); free (is_insn_merge_attempted); VEC_free (rtx, heap, zeinsn_list); |