From: Eric Botcazou <ebotca...@adacore.com>
This adds the missing guard to prevent the reduction from being used when
the target does not provide or cannot synthesize a high-part multiply.
gcc/ada/
* gcc-interface/trans.cc (gnat_to_gnu) <N_Op_Mod>: Fix formatting.
* gcc-interface/utils2.cc: Include optabs-query.h.
(fast_modulo_reduction): Call can_mult_highpart_p on the TYPE_MODE
before generating a high-part multiply. Fix formatting.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/gcc-interface/trans.cc | 2 +-
gcc/ada/gcc-interface/utils2.cc | 12 +++++++-----
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/gcc/ada/gcc-interface/trans.cc b/gcc/ada/gcc-interface/trans.cc
index 7c5282602b2..83ed17bff84 100644
--- a/gcc/ada/gcc-interface/trans.cc
+++ b/gcc/ada/gcc-interface/trans.cc
@@ -7323,7 +7323,7 @@ gnat_to_gnu (Node_Id gnat_node)
pair in the needed precision up to the word size. But not when
optimizing for size, because it will be longer than a div+mul+sub
sequence. */
- else if (!optimize_size
+ else if (!optimize_size
&& (code == FLOOR_MOD_EXPR || code == TRUNC_MOD_EXPR)
&& TYPE_UNSIGNED (gnu_type)
&& TYPE_PRECISION (gnu_type) <= BITS_PER_WORD
diff --git a/gcc/ada/gcc-interface/utils2.cc b/gcc/ada/gcc-interface/utils2.cc
index a37eccc4cfb..d101d7729bf 100644
--- a/gcc/ada/gcc-interface/utils2.cc
+++ b/gcc/ada/gcc-interface/utils2.cc
@@ -35,6 +35,7 @@
#include "builtins.h"
#include "expmed.h"
#include "fold-const.h"
+#include "optabs-query.h"
#include "stor-layout.h"
#include "stringpool.h"
#include "varasm.h"
@@ -558,11 +559,11 @@ fast_modulo_reduction (tree op, tree modulus, unsigned
int precision)
op / d = (op * multiplier) >> shifter
- But choose_multiplier provides a slightly different interface:
+ But choose_multiplier provides a slightly different interface:
- op / d = (op h* multiplier) >> reduced_shifter
+ op / d = (op h* multiplier) >> reduced_shifter
- that makes things easier by using a high-part multiplication. */
+ that makes things easier by using a high-part multiplication. */
mh = choose_multiplier (d, type_precision, precision, &ml, &post_shift);
/* If the suggested multiplier is more than TYPE_PRECISION bits, we can
@@ -577,8 +578,9 @@ fast_modulo_reduction (tree op, tree modulus, unsigned int
precision)
pre_shift = 0;
/* If the suggested multiplier is still more than TYPE_PRECISION bits,
- try again with a larger type up to the word size. */
- if (mh != 0)
+ or the TYPE_MODE does not have a high-part multiply, try again with
+ a larger type up to the word size. */
+ if (mh != 0 || !can_mult_highpart_p (TYPE_MODE (type), true))
{
if (type_precision < BITS_PER_WORD)
{
--
2.45.1
