In PR 106677, I noticed that on the trunk we were producing: ``` _25 = SR.116_117 == 0; _27 = (unsigned char) _25; _32 = _27 | SR.116_117; ``` >From `SR.115_117 != 0 ? SR.115_117 : 1` Rather than: ``` _119 = MAX_EXPR <1, SR.115_117>; ``` Or (rather) ``` _119 = SR.115_117 | 1; ``` Due to the order of the patterns.
Committed as approved with the new comment and testcase. Bootstrapped and tested on x86_64-linux-gnu with no regressions. gcc/ChangeLog: * match.pd (`a ? one_zero : one_zero`): Move below detection of minmax. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/phi-opt-34.c: New test. --- gcc/match.pd | 42 ++++++++++++---------- gcc/testsuite/gcc.dg/tree-ssa/phi-opt-34.c | 23 ++++++++++++ 2 files changed, 47 insertions(+), 18 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-34.c diff --git a/gcc/match.pd b/gcc/match.pd index d9f35e9e25b..fa598d5ca2e 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -4961,24 +4961,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) ) ) -(simplify - (cond @0 zero_one_valued_p@1 zero_one_valued_p@2) - (switch - /* bool0 ? bool1 : 0 -> bool0 & bool1 */ - (if (integer_zerop (@2)) - (bit_and (convert @0) @1)) - /* bool0 ? 0 : bool2 -> (bool0^1) & bool2 */ - (if (integer_zerop (@1)) - (bit_and (bit_xor (convert @0) { build_one_cst (type); } ) @2)) - /* bool0 ? 1 : bool2 -> bool0 | bool2 */ - (if (integer_onep (@1)) - (bit_ior (convert @0) @2)) - /* bool0 ? bool1 : 1 -> (bool0^1) | bool1 */ - (if (integer_onep (@2)) - (bit_ior (bit_xor (convert @0) @2) @1)) - ) -) - /* Optimize # x_5 in range [cst1, cst2] where cst2 = cst1 + 1 x_5 ? cstN ? cst4 : cst3 @@ -5309,6 +5291,30 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) && integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, @3, @1))) (max @2 @4)))))) +#if GIMPLE +/* These patterns should be after min/max detection as simplifications + of `(type)(zero_one ==/!= 0)` to `(type)(zero_one)` + and `(type)(zero_one^1)` are not done yet. See PR 110637. + Even without those, reaching min/max/and/ior faster is better. */ +(simplify + (cond @0 zero_one_valued_p@1 zero_one_valued_p@2) + (switch + /* bool0 ? bool1 : 0 -> bool0 & bool1 */ + (if (integer_zerop (@2)) + (bit_and (convert @0) @1)) + /* bool0 ? 0 : bool2 -> (bool0^1) & bool2 */ + (if (integer_zerop (@1)) + (bit_and (bit_xor (convert @0) { build_one_cst (type); } ) @2)) + /* bool0 ? 1 : bool2 -> bool0 | bool2 */ + (if (integer_onep (@1)) + (bit_ior (convert @0) @2)) + /* bool0 ? bool1 : 1 -> (bool0^1) | bool1 */ + (if (integer_onep (@2)) + (bit_ior (bit_xor (convert @0) @2) @1)) + ) +) +#endif + /* X != C1 ? -X : C2 simplifies to -X when -C1 == C2. */ (simplify (cond (ne @0 INTEGER_CST@1) (negate@3 @0) INTEGER_CST@2) diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-34.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-34.c new file mode 100644 index 00000000000..157c3ea9a0b --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-34.c @@ -0,0 +1,23 @@ +/* { dg-do compile } */ +/* Disable early phiopt1 as early ccp1 does not export non-zero bits + so at the point of phiopt1, we don't know that a is [0,1] range */ +/* { dg-options "-O1 -fdisable-tree-phiopt1 -fdump-tree-phiopt2-folding"} */ + +unsigned f(unsigned a) +{ + a &= 1; + if (a > 0) + return a; + return 1; +} +/* PHIOPT2 should be able to change this into just return 1; + (which was `MAX<a, 1>` or `a | 1` but since a is known to be a + range of [0,1], it should be folded into 1) + And not fold it into `(a == 0) | a`. */ +/* { dg-final { scan-tree-dump-not " == " "phiopt2" } } */ +/* { dg-final { scan-tree-dump-not " if " "phiopt2" } } */ +/* { dg-final { scan-tree-dump-not "Folded into the sequence:" "phiopt2" } } */ +/* { dg-final { scan-tree-dump "return 1;" "phiopt2" } } */ +/* We want to make sure that phiopt2 is happening and not some other pass + before it does the transformation. */ +/* { dg-final { scan-tree-dump "Removing basic block" "phiopt2" } } */ -- 2.31.1