tree-optimization/106379 - add missing ~(a ^ b) folding for _Bool
The following makes sure to fold ~(a ^ b) to a == b for truth values (but not vectors, we'd have to check for vector support of equality). That turns the PR106379 testcase into a ranger one. Note that while we arrive at ~(a ^ b) in a convoluted way from original !a == !b one can eventually write the expression this way directly as well. PR tree-optimization/106379 * match.pd (~(a ^ b) -> a == b): New pattern. * gcc.dg/pr106379-1.c: New testcase.
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@ -1938,6 +1938,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
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(if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
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(bit_not (bit_xor (view_convert @0) @1))))
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/* ~(a ^ b) is a == b for truth valued a and b. */
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(simplify
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(bit_not (bit_xor:s truth_valued_p@0 truth_valued_p@1))
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(if (!VECTOR_TYPE_P (type))
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(convert (eq @0 @1))))
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/* (x & ~m) | (y & m) -> ((x ^ y) & m) ^ x */
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(simplify
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(bit_ior:c (bit_and:cs @0 (bit_not @2)) (bit_and:cs @1 @2))
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@ -0,0 +1,9 @@
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/* { dg-do compile } */
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/* { dg-options "-O -fdump-tree-forwprop1" } */
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_Bool foo (_Bool a, _Bool b)
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{
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return !a == !b;
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}
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/* { dg-final { scan-tree-dump "\[ab\]_\[0-9\]+\\(D\\) == \[ba\]_\[0-9\]+\\(D\\)" "forwprop1" } } */
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