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re PR target/93002 (while(i--) optimization)

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PR target/93002
	* config/i386/i386.md (dec reg; cmp $-1, reg; jne lab): New
	define_peephole2.

	* gcc.target/i386/pr93002.c: New test.

From-SVN: r279632
This commit is contained in:
Jakub Jelinek 2019-12-20 09:22:46 +01:00 committed by Jakub Jelinek
parent 9be3ac5d63
commit 99675d5c45
4 changed files with 63 additions and 0 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2019-12-20 Jakub Jelinek <jakub@redhat.com>
PR target/93002
* config/i386/i386.md (dec reg; cmp $-1, reg; jne lab): New
define_peephole2.
2019-12-19 Julian Brown <julian@codesourcery.com>
* gimplify.c (gimplify_omp_var_data): Add GOVD_MAP_HAS_ATTACHMENTS.

30
gcc/config/i386/i386.md
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@ -6503,6 +6503,36 @@
[(set (reg:CC FLAGS_REG)
(compare:CC (match_dup 0) (match_dup 1)))])
;; decl %eax; cmpl $-1, %eax; jne .Lxx; can be optimized into
;; subl $1, %eax; jnc .Lxx;
(define_peephole2
[(parallel
[(set (match_operand:SWI 0 "general_reg_operand")
(plus:SWI (match_dup 0) (const_int -1)))
(clobber (reg FLAGS_REG))])
(set (reg:CCZ FLAGS_REG)
(compare:CCZ (match_dup 0) (const_int -1)))
(set (pc)
(if_then_else (match_operator 1 "bt_comparison_operator"
[(reg:CCZ FLAGS_REG) (const_int 0)])
(match_operand 2)
(pc)))]
"peep2_regno_dead_p (3, FLAGS_REG)"
[(parallel
[(set (reg:CC FLAGS_REG)
(compare:CC (match_dup 0) (const_int 1)))
(set (match_dup 0)
(minus:SWI (match_dup 0) (const_int 1)))])
(set (pc)
(if_then_else (match_dup 3)
(match_dup 2)
(pc)))]
{
rtx cc = gen_rtx_REG (CCmode, FLAGS_REG);
operands[3] = gen_rtx_fmt_ee (GET_CODE (operands[1]) == NE
? GEU : LTU, VOIDmode, cc, const0_rtx);
})
(define_insn "*subsi_3_zext"
[(set (reg FLAGS_REG)
(compare (match_operand:SI 1 "register_operand" "0")

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2019-12-20 Jakub Jelinek <jakub@redhat.com>
PR target/93002
* gcc.target/i386/pr93002.c: New test.
2019-12-19 Julian Brown <julian@codesourcery.com>
* gfortran.dg/goacc/derived-types.f90: New test.

22
gcc/testsuite/gcc.target/i386/pr93002.c Normal file
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@ -0,0 +1,22 @@
/* PR target/93002 */
/* { dg-do compile } */
/* { dg-options "-O2" } */
/* { dg-final { scan-assembler-not "cmp\[^\n\r]*-1" } } */
volatile int sink;
void
foo (void)
{
unsigned i = 1000;
while (i--)
sink = i;
}
void
bar (void)
{
int i = 2000;
while (i--)
sink = i;
}