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| author | Andrew Pinski <quic_apinski@quicinc.com> | 2024-01-10 14:25:37 -0800 |
|---|---|---|
| committer | Andrew Pinski <quic_apinski@quicinc.com> | 2024-01-11 10:01:22 -0800 |
| commit | 7f56a90269b393fcc55ef08e0990fafb7b1c24b4 (patch) | |
| tree | 65ad4e66129bd79733c39a79f4944598abcdeebc /gcc | |
| parent | cd2022f39297198adad0e284f8780cb3d83d0f85 (diff) | |
| download | gcc-7f56a90269b393fcc55ef08e0990fafb7b1c24b4.zip gcc-7f56a90269b393fcc55ef08e0990fafb7b1c24b4.tar.gz gcc-7f56a90269b393fcc55ef08e0990fafb7b1c24b4.tar.bz2 | |
match: Delay folding of 1/x into `(x+1u)<2u?x:0` until late [PR113301]
Since currently ranger does not work with the complexity of COND_EXPR in
some cases so delaying the simplification of `1/x` for signed types
help code generation.
tree-ssa/divide-8.c is a new testcase where this can help.
Bootstrapped and tested on x86_64-linux-gnu with no regressions.
PR tree-optimization/113301
gcc/ChangeLog:
* match.pd (`1/x`): Delay signed case until late.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/divide-8.c: New test.
Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/match.pd | 12 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/divide-8.c | 13 |
2 files changed, 20 insertions, 5 deletions
diff --git a/gcc/match.pd b/gcc/match.pd index abbd037..0bcf315 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -560,7 +560,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) 1 / X -> X >= -1 && X <= 1 ? X : 0 for signed integer X. But not for 1 / 0 so that we can get proper warnings and errors, and not for 1-bit integers as they are edge cases better handled - elsewhere. */ + elsewhere. Delay the conversion of the signed division until late + because `1 / X` is simplier to handle than the resulting COND_EXPR. */ (simplify (trunc_div integer_onep@0 @1) (if (INTEGRAL_TYPE_P (type) @@ -569,10 +570,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) && (!flag_non_call_exceptions || tree_expr_nonzero_p (@1))) (if (TYPE_UNSIGNED (type)) (convert (eq:boolean_type_node @1 { build_one_cst (type); })) - (with { tree utype = unsigned_type_for (type); } - (cond (le (plus (convert:utype @1) { build_one_cst (utype); }) - { build_int_cst (utype, 2); }) - @1 { build_zero_cst (type); }))))) + (if (!canonicalize_math_p ()) + (with { tree utype = unsigned_type_for (type); } + (cond (le (plus (convert:utype @1) { build_one_cst (utype); }) + { build_int_cst (utype, 2); }) + @1 { build_zero_cst (type); })))))) /* Combine two successive divisions. Note that combining ceil_div and floor_div is trickier and combining round_div even more so. */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/divide-8.c b/gcc/testsuite/gcc.dg/tree-ssa/divide-8.c new file mode 100644 index 0000000..b814908 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/divide-8.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fdump-tree-optimized" } */ +/* PR tree-optimization/113301 */ +/* We should figure out that 1/(x+1) range is [-1,1] + and then /2 is always 0. */ + +void link_error(void); +void func(int x){ + int c=(1/(x+1))/2; + if (c != 0) + link_error(); +} +/* { dg-final { scan-tree-dump-not "link_error " "optimized" } } */ |