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| author | Jiufu Guo <guojiufu@linux.ibm.com> | 2023-09-06 21:38:11 +0800 |
|---|---|---|
| committer | guojiufu <guojiufu@linux.ibm.com> | 2023-09-13 09:31:53 +0800 |
| commit | 8d8bc560b6ab7f3153db23ffb37157528e5b2c9a (patch) | |
| tree | a390e8eb40bcba37786d317a1d334f7ae39b04b4 /gcc/match.pd | |
| parent | a1c20158c68fe537c485006fe95ca198b6d15005 (diff) | |
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Checking undefined_p before using the vr
For pattern "(X + C) / N": "div (plus@3 @0 INTEGER_CST@1) INTEGER_CST@2)",
Even if "X" has value-range and "X + C" does not overflow, "@3" may still
be undefined. Like below example:
_3 = _2 + -5;
if (0 != 0)
goto <bb 3>; [34.00%]
else
goto <bb 4>; [66.00%]
;; succ: 3
;; 4
;; basic block 3, loop depth 0
;; pred: 2
_5 = _3 / 5;
;; succ: 4
The whole pattern "(_2 + -5 ) / 5" is in "bb 3", but "bb 3" would be
unreachable (because "if (0 != 0)" is always false).
And "get_range_query (cfun)->range_of_expr (vr3, @3)" is checked in
"bb 3", "range_of_expr" gets an "undefined vr3". Where "@3" is "_5".
So, before using "vr3", it would be safe to check "!vr3.undefined_p ()".
PR tree-optimization/111303
gcc/ChangeLog:
* match.pd ((X - N * M) / N): Add undefined_p checking.
((X + N * M) / N): Likewise.
((X + C) div_rshift N): Likewise.
gcc/testsuite/ChangeLog:
* gcc.dg/pr111303.c: New test.
Diffstat (limited to 'gcc/match.pd')
| -rw-r--r-- | gcc/match.pd | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/gcc/match.pd b/gcc/match.pd index 39c7ea1..693638f 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -975,6 +975,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* "X+(N*M)" doesn't overflow. */ && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr3) && get_range_query (cfun)->range_of_expr (vr4, @4) + && !vr4.undefined_p () /* "X+N*M" is not with opposite sign as "X". */ && (TYPE_UNSIGNED (type) || (vr0.nonnegative_p () && vr4.nonnegative_p ()) @@ -995,6 +996,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* "X - (N*M)" doesn't overflow. */ && range_op_handler (MINUS_EXPR).overflow_free_p (vr0, vr3) && get_range_query (cfun)->range_of_expr (vr4, @4) + && !vr4.undefined_p () /* "X-N*M" is not with opposite sign as "X". */ && (TYPE_UNSIGNED (type) || (vr0.nonnegative_p () && vr4.nonnegative_p ()) @@ -1025,6 +1027,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* "X+C" doesn't overflow. */ && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr1) && get_range_query (cfun)->range_of_expr (vr3, @3) + && !vr3.undefined_p () /* "X+C" and "X" are not of opposite sign. */ && (TYPE_UNSIGNED (type) || (vr0.nonnegative_p () && vr3.nonnegative_p ()) |