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Diffstat (limited to 'gcc/tree-ssa-math-opts.c')
| -rw-r--r-- | gcc/tree-ssa-math-opts.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c index 8902d85..1496520 100644 --- a/gcc/tree-ssa-math-opts.c +++ b/gcc/tree-ssa-math-opts.c @@ -3094,6 +3094,7 @@ convert_mult_to_fma (gimple *mul_stmt, tree op1, tree op2, && (tree_to_shwi (TYPE_SIZE (type)) <= PARAM_VALUE (PARAM_AVOID_FMA_MAX_BITS))); bool defer = check_defer; + bool seen_negate_p = false; /* Make sure that the multiplication statement becomes dead after the transformation, thus that all uses are transformed to FMAs. This means we assume that an FMA operation has the same cost @@ -3127,6 +3128,12 @@ convert_mult_to_fma (gimple *mul_stmt, tree op1, tree op2, ssa_op_iter iter; use_operand_p usep; + /* If (due to earlier missed optimizations) we have two + negates of the same value, treat them as equivalent + to a single negate with multiple uses. */ + if (seen_negate_p) + return false; + result = gimple_assign_lhs (use_stmt); /* Make sure the negate statement becomes dead with this @@ -3145,7 +3152,7 @@ convert_mult_to_fma (gimple *mul_stmt, tree op1, tree op2, if (gimple_bb (use_stmt) != gimple_bb (mul_stmt)) return false; - negate_p = true; + negate_p = seen_negate_p = true; } tree cond, else_value, ops[3]; |