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_apin...@quicinc.com> --- gcc/match.pd | 12 +++++++----- gcc/testsuite/gcc.dg/tree-ssa/divide-8.c | 13 +++++++++++++ 2 files changed, 20 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/divide-8.c diff --git a/gcc/match.pd b/gcc/match.pd index d75babd86c2..81a389057cf 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 00000000000..b8149088177 --- /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" } } */ -- 2.39.3