diff --git a/gcc/match.pd b/gcc/match.pd index a63b649..5089b07 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -3559,6 +3559,29 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) && wi::lshift (wi::to_wide (@0), cand) == wi::to_wide (@2)) (cmp @1 { build_int_cst (TREE_TYPE (@1), cand); })))))) +/* Fold ((X << C1) & C2) cmp C3 into (X & (C2 >> C1)) cmp (C3 >> C1) + ((X >> C1) & C2) cmp C3 into (X & (C2 << C1)) cmp (C3 << C1). */ +(for cmp (ne eq) + (simplify + (cmp (bit_and:s (lshift:s @0 INTEGER_CST@1) INTEGER_CST@2) INTEGER_CST@3) + (if (tree_fits_shwi_p (@1) + && tree_to_shwi (@1) > 0 + && tree_to_shwi (@1) < TYPE_PRECISION (TREE_TYPE (@0)) + && tree_to_shwi (@1) <= wi::ctz (wi::to_wide (@3))) + (with { wide_int c1 = wi::to_wide (@1); + wide_int c2 = wi::lrshift (wi::to_wide (@2), c1); + wide_int c3 = wi::lrshift (wi::to_wide (@3), c1); } + (cmp (bit_and @0 { wide_int_to_tree (TREE_TYPE (@0), c2); }) + { wide_int_to_tree (TREE_TYPE (@0), c3); })))) + (simplify + (cmp (bit_and:s (rshift:s @0 INTEGER_CST@1) INTEGER_CST@2) INTEGER_CST@3) + (if (tree_fits_shwi_p (@1) + && tree_to_shwi (@1) > 0 + && tree_to_shwi (@1) < TYPE_PRECISION (TREE_TYPE (@0)) + && tree_to_shwi (@1) <= wi::clz (wi::to_wide (@2)) + && tree_to_shwi (@1) <= wi::clz (wi::to_wide (@3))) + (cmp (bit_and @0 (lshift @2 @1)) (lshift @3 @1))))) + /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1)) (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1)) if the new mask might be further optimized. */ diff --git a/gcc/testsuite/gcc.dg/pr94026.c b/gcc/testsuite/gcc.dg/pr94026.c new file mode 100644 index 0000000..489b978 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr94026.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ + +int f1(int x) { return ((x >> 8) & 6) != 0; } +int f2(int x) { return ((x << 2) & 24) != 0; } +int f3(unsigned x) { return ((x << 2) & 15) != 0; } +int f4(unsigned x) { return ((x >> 2) & 14) != 0; } + +int fifth (int c) +{ + int a = (c >> 8) & 7; + + if (a >= 2) { + return 1; + } else { + return 0; + } +} +/* { dg-final { scan-tree-dump-not " << " "optimized" } } */ +/* { dg-final { scan-tree-dump-not " >> " "optimized" } } */ +