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| author | Zack Weinberg <zackw@stanford.edu> | 2001-05-17 00:53:25 +0000 |
|---|---|---|
| committer | Zack Weinberg <zack@gcc.gnu.org> | 2001-05-17 00:53:25 +0000 |
| commit | a3e991f29855a3d949802c7e18aa09604e9ed191 (patch) | |
| tree | d46d91043ac8d0ca2c252b6699ce8f8098b1a562 /gcc/config | |
| parent | 12b38507e683988f660c80b6910ec4a9231eb2a0 (diff) | |
| download | gcc-a3e991f29855a3d949802c7e18aa09604e9ed191.zip gcc-a3e991f29855a3d949802c7e18aa09604e9ed191.tar.gz gcc-a3e991f29855a3d949802c7e18aa09604e9ed191.tar.bz2 | |
i386.md: Add two peepholes to clean up code generated by cmpstr* expanders.
* i386.md: Add two peepholes to clean up code generated by
cmpstr* expanders.
From-SVN: r42183
Diffstat (limited to 'gcc/config')
| -rw-r--r-- | gcc/config/i386/i386.md | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md index b85e585..a5bad66 100644 --- a/gcc/config/i386/i386.md +++ b/gcc/config/i386/i386.md @@ -15463,6 +15463,91 @@ [(set_attr "type" "str") (set_attr "mode" "QI") (set_attr "prefix_rep" "1")]) + +;; Peephole optimizations to clean up after cmpstr*. This should be +;; handled in combine, but it is not currently up to the task. +;; When used for their truth value, the cmpstr* expanders generate +;; code like this: +;; +;; repz cmpsb +;; seta %al +;; setb %dl +;; cmpb %al, %dl +;; jcc label +;; +;; The intermediate three instructions are unnecessary. + +;; This one handles cmpstr*_nz_1... +(define_peephole2 + [(parallel[ + (set (reg:CC 17) + (compare:CC (mem:BLK (match_operand 4 "register_operand" "")) + (mem:BLK (match_operand 5 "register_operand" "")))) + (use (match_operand 6 "register_operand" "")) + (use (match_operand:SI 3 "immediate_operand" "")) + (use (reg:SI 19)) + (clobber (match_operand 0 "register_operand" "")) + (clobber (match_operand 1 "register_operand" "")) + (clobber (match_operand 2 "register_operand" ""))]) + (set (match_operand:QI 7 "register_operand" "") + (gtu:QI (reg:CC 17) (const_int 0))) + (set (match_operand:QI 8 "register_operand" "") + (ltu:QI (reg:CC 17) (const_int 0))) + (set (reg 17) + (compare (match_dup 7) (match_dup 8))) + ] + "" + [(parallel[ + (set (reg:CC 17) + (compare:CC (mem:BLK (match_dup 4)) + (mem:BLK (match_dup 5)))) + (use (match_dup 6)) + (use (match_dup 3)) + (use (reg:SI 19)) + (clobber (match_dup 0)) + (clobber (match_dup 1)) + (clobber (match_dup 2))])] + "") + +;; ...and this one handles cmpstr*_1. +(define_peephole2 + [(parallel[ + (set (reg:CC 17) + (if_then_else:CC (ne (match_operand 6 "register_operand" "") + (const_int 0)) + (compare:CC (mem:BLK (match_operand 4 "register_operand" "")) + (mem:BLK (match_operand 5 "register_operand" ""))) + (const_int 0))) + (use (match_operand:SI 3 "immediate_operand" "")) + (use (reg:CC 17)) + (use (reg:SI 19)) + (clobber (match_operand 0 "register_operand" "")) + (clobber (match_operand 1 "register_operand" "")) + (clobber (match_operand 2 "register_operand" ""))]) + (set (match_operand:QI 7 "register_operand" "") + (gtu:QI (reg:CC 17) (const_int 0))) + (set (match_operand:QI 8 "register_operand" "") + (ltu:QI (reg:CC 17) (const_int 0))) + (set (reg 17) + (compare (match_dup 7) (match_dup 8))) + ] + "" + [(parallel[ + (set (reg:CC 17) + (if_then_else:CC (ne (match_dup 6) + (const_int 0)) + (compare:CC (mem:BLK (match_dup 4)) + (mem:BLK (match_dup 5))) + (const_int 0))) + (use (match_dup 3)) + (use (reg:CC 17)) + (use (reg:SI 19)) + (clobber (match_dup 0)) + (clobber (match_dup 1)) + (clobber (match_dup 2))])] + "") + + ;; Conditional move instructions. |