Use conditional internal functions in if-conversion
This patch uses IFN_COND_* to vectorise conditionally-executed,
potentially-trapping arithmetic, such as most floating-point
ops with -ftrapping-math. E.g.:
if (cond) { ... x = a + b; ... }
becomes:
...
x = .COND_ADD (cond, a, b, else_value);
...
When this transformation is done on its own, the value of x for
!cond isn't important, so else_value is simply the target's
preferred_else_value (i.e. the value it can handle the most
efficiently).
However, the patch also looks for the equivalent of:
y = cond ? x : c;
in which the "then" value is the result of the conditionally-executed
operation and the "else" value "c" is some value that is available at x.
In that case we can instead use:
x = .COND_ADD (cond, a, b, c);
and replace uses of y with uses of x.
The patch also looks for:
y = !cond ? c : x;
which can be transformed in the same way. This involved adding a new
utility function inverse_conditions_p, which was already open-coded
in a more limited way in match.pd.
2018-07-12 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
* fold-const.h (inverse_conditions_p): Declare.
* fold-const.c (inverse_conditions_p): New function.
* match.pd: Use inverse_conditions_p. Add folds of view_converts
that test the inverse condition of a conditional internal function.
* internal-fn.h (vectorized_internal_fn_supported_p): Declare.
* internal-fn.c (internal_fn_mask_index): Handle conditional
internal functions.
(vectorized_internal_fn_supported_p): New function.
* tree-if-conv.c: Include internal-fn.h and fold-const.h.
(any_pred_load_store): Replace with...
(need_to_predicate): ...this new variable.
(redundant_ssa_names): New variable.
(ifcvt_can_use_mask_load_store): Move initial checks to...
(ifcvt_can_predicate): ...this new function. Handle tree codes
for which a conditional internal function exists.
(if_convertible_gimple_assign_stmt_p): Use ifcvt_can_predicate
instead of ifcvt_can_use_mask_load_store. Update after variable
name change.
(predicate_load_or_store): New function, split out from
predicate_mem_writes.
(check_redundant_cond_expr): New function.
(value_available_p): Likewise.
(predicate_rhs_code): Likewise.
(predicate_mem_writes): Rename to...
(predicate_statements): ...this. Use predicate_load_or_store
and predicate_rhs_code.
(combine_blocks, tree_if_conversion): Update after above name changes.
(ifcvt_local_dce): Handle redundant_ssa_names.
* tree-vect-patterns.c (vect_recog_mask_conversion_pattern): Handle
general conditional functions.
* tree-vect-stmts.c (vectorizable_call): Likewise.
gcc/testsuite/
* gcc.dg/vect/vect-cond-arith-4.c: New test.
* gcc.dg/vect/vect-cond-arith-5.c: Likewise.
* gcc.target/aarch64/sve/cond_arith_1.c: Likewise.
* gcc.target/aarch64/sve/cond_arith_1_run.c: Likewise.
* gcc.target/aarch64/sve/cond_arith_2.c: Likewise.
* gcc.target/aarch64/sve/cond_arith_2_run.c: Likewise.
* gcc.target/aarch64/sve/cond_arith_3.c: Likewise.
* gcc.target/aarch64/sve/cond_arith_3_run.c: Likewise.
From-SVN: r262589
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