This allows unsigned types if the inner type where the negation is located has greater than or equal to precision than the outer type.
branchless-cond.c needs to be updated since now we change it to use a multiply rather than still having (-a)&c in there. OK? Bootstrapped and tested on x86_64-linux-gnu. gcc/ChangeLog: * match.pd (`X & -Y -> X * Y`): Allow for truncation and the same type for unsigned types. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/branchless-cond.c: Update testcase. --- gcc/match.pd | 5 ++++- gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c | 6 +++--- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/gcc/match.pd b/gcc/match.pd index 4ad037d641a..7b95b63cee4 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -2058,7 +2058,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (if (INTEGRAL_TYPE_P (type) && INTEGRAL_TYPE_P (TREE_TYPE (@0)) && TREE_CODE (TREE_TYPE (@0)) != BOOLEAN_TYPE - && !TYPE_UNSIGNED (TREE_TYPE (@0))) + /* Sign extending of the neg or a truncation of the neg + is needed. */ + && (!TYPE_UNSIGNED (TREE_TYPE (@0)) + || TYPE_PRECISION (type) <= TYPE_PRECISION (TREE_TYPE (@0)))) (mult (convert @0) @1))) /* Narrow integer multiplication by a zero_one_valued_p operand. diff --git a/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c b/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c index 68087ae6568..e063dc4bb5f 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c @@ -21,6 +21,6 @@ int f4(unsigned int x, unsigned int y, unsigned int z) return ((x & 1) != 0) ? z | y : y; } -/* { dg-final { scan-tree-dump-times " -" 4 "optimized" } } */ -/* { dg-final { scan-tree-dump-times " & " 8 "optimized" } } */ -/* { dg-final { scan-tree-dump-not "if" "optimized" } } */ +/* { dg-final { scan-tree-dump-times " \\\*" 4 "optimized" } } */ +/* { dg-final { scan-tree-dump-times " & " 4 "optimized" } } */ +/* { dg-final { scan-tree-dump-not "if " "optimized" } } */ -- 2.31.1