From 94912212d3d1be0b1c490e9b5f45165ef5f30d8a Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Thu, 25 Nov 2021 10:47:24 +0100 Subject: [PATCH] match.pd: Fix up the recent bitmask_inv_cst_vector_p simplification [PR103417] The following testcase is miscompiled since the r12-5489-g0888d6bbe97e10 changes. The simplification triggers on (x & 4294967040U) >= 0U and turns it into: x <= 255U which is incorrect, it should fold to 1 because unsigned >= 0U is always true and normally the /* Non-equality compare simplifications from fold_binary */ (if (wi::to_wide (cst) == min) (if (cmp == GE_EXPR) { constant_boolean_node (true, type); }) simplification folds that, but this simplification was done earlier. The simplification correctly doesn't include lt which has the same reason why it shouldn't be handled, we'll fold it to 0 elsewhere. But, IMNSHO while it isn't incorrect to handle le and gt there, it is unnecessary. Because (x & cst) <= 0U and (x & cst) > 0U should never appear, again in /* Non-equality compare simplifications from fold_binary */ we have a simplification for it: (if (cmp == LE_EXPR) (eq @2 @1)) (if (cmp == GT_EXPR) (ne @2 @1)))) This is done for (cmp (convert?@2 @0) uniform_integer_cst_p@1) and so should be done for both integers and vectors. As the bitmask_inv_cst_vector_p simplification only handles eq and ne for signed types, I think it can be simplified to just following patch. 2021-11-25 Jakub Jelinek PR tree-optimization/103417 * match.pd ((X & Y) CMP 0): Only handle eq and ne. Commonalize common tests. * gcc.c-torture/execute/pr103417.c: New test. --- gcc/match.pd | 22 ++++++++----------- .../gcc.c-torture/execute/pr103417.c | 11 ++++++++++ 2 files changed, 20 insertions(+), 13 deletions(-) create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr103417.c diff --git a/gcc/match.pd b/gcc/match.pd index 5adcd6bd02c..39fd77ddc4a 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -5214,20 +5214,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* Transform comparisons of the form (X & Y) CMP 0 to X CMP2 Z where ~Y + 1 == pow2 and Z = ~Y. */ (for cst (VECTOR_CST INTEGER_CST) - (for cmp (le eq ne ge gt) - icmp (le le gt le gt) - (simplify - (cmp (bit_and:c@2 @0 cst@1) integer_zerop) - (with { tree csts = bitmask_inv_cst_vector_p (@1); } - (switch - (if (csts && TYPE_UNSIGNED (TREE_TYPE (@1)) - && (VECTOR_TYPE_P (TREE_TYPE (@1)) || single_use (@2))) - (icmp @0 { csts; })) - (if (csts && !TYPE_UNSIGNED (TREE_TYPE (@1)) - && (cmp == EQ_EXPR || cmp == NE_EXPR) - && (VECTOR_TYPE_P (TREE_TYPE (@1)) || single_use (@2))) + (for cmp (eq ne) + icmp (le gt) + (simplify + (cmp (bit_and:c@2 @0 cst@1) integer_zerop) + (with { tree csts = bitmask_inv_cst_vector_p (@1); } + (if (csts && (VECTOR_TYPE_P (TREE_TYPE (@1)) || single_use (@2))) + (if (TYPE_UNSIGNED (TREE_TYPE (@1))) + (icmp @0 { csts; }) (with { tree utype = unsigned_type_for (TREE_TYPE (@1)); } - (icmp (convert:utype @0) { csts; })))))))) + (icmp (convert:utype @0) { csts; })))))))) /* -A CMP -B -> B CMP A. */ (for cmp (tcc_comparison) diff --git a/gcc/testsuite/gcc.c-torture/execute/pr103417.c b/gcc/testsuite/gcc.c-torture/execute/pr103417.c new file mode 100644 index 00000000000..0fef8908036 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/pr103417.c @@ -0,0 +1,11 @@ +/* PR tree-optimization/103417 */ + +struct { int a : 8; int b : 24; } c = { 0, 1 }; + +int +main () +{ + if (c.b && !c.b) + __builtin_abort (); + return 0; +}