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postreload: Fix up postreload combine [PR93402]

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The following testcase is miscompiled, because the postreload pass changes:
-(insn 14 13 23 2 (parallel [
-            (set (reg:DI 1 dx [94])
-                (plus:DI (reg:DI 1 dx [95])
-                    (reg:DI 5 di [92])))
-            (clobber (reg:CC 17 flags))
-        ]) "pr93402.c":8:30 186 {*adddi_1}
-     (expr_list:REG_EQUAL (plus:DI (reg:DI 5 di [92])
-            (const_int 111111111111 [0x19debd01c7]))
-        (nil)))
-(insn 23 14 25 2 (set (reg:SI 0 ax)
+(insn 23 13 25 2 (set (reg:SI 0 ax)
         (const_int 0 [0])) "pr93402.c":10:1 67 {*movsi_internal}
      (nil))
 (insn 25 23 26 2 (use (reg:SI 0 ax)) "pr93402.c":10:1 -1
      (nil))
-(insn 26 25 35 2 (use (reg:DI 1 dx)) "pr93402.c":10:1 -1
+(insn 26 25 35 2 (use (plus:DI (reg:DI 1 dx [95])
+            (reg:DI 5 di [92]))) "pr93402.c":10:1 -1
      (nil))
A USE insn is not a normal insn and verify_changes called from
apply_change_group is happy about any changes into it.
The following patch avoids this optimization if we were to change
the USE operand (this routine only changes a reg into (plus reg reg2)).

2020-01-23  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/93402
	* postreload.c (reload_combine_recognize_pattern): Don't try to adjust
	USE insns.

	* gcc.c-torture/execute/pr93402.c: New test.
This commit is contained in:
Jakub Jelinek 2020-01-23 20:08:22 +01:00
parent c91072247e
commit 32667e04c7
4 changed files with 36 additions and 0 deletions
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6
gcc/ChangeLog
View file

@ -1,3 +1,9 @@
2020-01-23 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/93402
* postreload.c (reload_combine_recognize_pattern): Don't try to adjust
USE insns.
2020-01-23 Dragan Mladjenovic <dmladjenovic@wavecomp.com>
* config.in: Regenerated.

4
gcc/postreload.c
View file

@ -1078,6 +1078,10 @@ reload_combine_recognize_pattern (rtx_insn *insn)
struct reg_use *use = reg_state[regno].reg_use + i;
if (GET_MODE (*use->usep) != mode)
return false;
/* Don't try to adjust (use (REGX)). */
if (GET_CODE (PATTERN (use->insn)) == USE
&& &XEXP (PATTERN (use->insn), 0) == use->usep)
return false;
}
/* Look for (set (REGX) (CONST_INT))

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2020-01-23 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/93402
* gcc.c-torture/execute/pr93402.c: New test.
2020-01-23 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/92804

21
gcc/testsuite/gcc.c-torture/execute/pr93402.c Normal file
View file

@ -0,0 +1,21 @@
/* PR rtl-optimization/93402 */
struct S { unsigned int a; unsigned long long b; };
__attribute__((noipa)) struct S
foo (unsigned long long x)
{
struct S ret;
ret.a = 0;
ret.b = x * 11111111111ULL + 111111111111ULL;
return ret;
}
int
main ()
{
struct S a = foo (1);
if (a.a != 0 || a.b != 122222222222ULL)
__builtin_abort ();
return 0;
}