Hi Richard,
Thanks for the review. Attached is the latest patch.
For testcase like cond_arith_1.c, with the patch, gcc ICE in fwprop. I
am limiting fwprop in cases like this. Is there a better fix for this?
index cf2c9de..2c99285 100644
--- a/gcc/fwprop.c
+++ b/gcc/fwprop.c
@@ -1358,6 +1358,15 @@ forward_propagate_and_simplify (df_ref use,
rtx_insn *def_insn, rtx def_set)
else
mode = GET_MODE (*loc);
+ /* TODO. We can't get the mode for
+ (set (reg:VNx16BI 109)
+ (unspec:VNx16BI [
+ (reg:SI 131)
+ (reg:SI 106)
+ ] UNSPEC_WHILE_LO))
+ Thus, bailout when it is UNSPEC and MODEs are not compatible. */
+ if (GET_MODE_CLASS (mode) != GET_MODE_CLASS (GET_MODE (reg)))
+ return false;
new_rtx = propagate_rtx (*loc, mode, reg, src,
optimize_bb_for_speed_p (BLOCK_FOR_INSN (use_insn)));
Thanks,
Kugan
On Mon, 3 Jun 2019 at 19:08, Richard Sandiford
<richard.sandif...@arm.com> wrote:
>
> Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org> writes:
> > diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
> > index b3fae5b..ad838dd 100644
> > --- a/gcc/tree-vect-loop-manip.c
> > +++ b/gcc/tree-vect-loop-manip.c
> > @@ -415,6 +415,7 @@ vect_set_loop_masks_directly (struct loop *loop,
> > loop_vec_info loop_vinfo,
> > bool might_wrap_p)
> > {
> > tree compare_type = LOOP_VINFO_MASK_COMPARE_TYPE (loop_vinfo);
> > + tree iv_type = LOOP_VINFO_MASK_IV_TYPE (loop_vinfo);
> > tree mask_type = rgm->mask_type;
> > unsigned int nscalars_per_iter = rgm->max_nscalars_per_iter;
> > poly_uint64 nscalars_per_mask = TYPE_VECTOR_SUBPARTS (mask_type);
> > @@ -445,11 +446,16 @@ vect_set_loop_masks_directly (struct loop *loop,
> > loop_vec_info loop_vinfo,
> > tree index_before_incr, index_after_incr;
> > gimple_stmt_iterator incr_gsi;
> > bool insert_after;
> > - tree zero_index = build_int_cst (compare_type, 0);
> > standard_iv_increment_position (loop, &incr_gsi, &insert_after);
> > - create_iv (zero_index, nscalars_step, NULL_TREE, loop, &incr_gsi,
> > +
> > + tree zero_index = build_int_cst (iv_type, 0);
> > + tree step = build_int_cst (iv_type,
> > + LOOP_VINFO_VECT_FACTOR (loop_vinfo));
> > + /* Creating IV of iv_type. */
>
> s/Creating/Create/
>
> > + create_iv (zero_index, step, NULL_TREE, loop, &incr_gsi,
> > insert_after, &index_before_incr, &index_after_incr);
> >
> > + zero_index = build_int_cst (compare_type, 0);
> > tree test_index, test_limit, first_limit;
> > gimple_stmt_iterator *test_gsi;
> > if (might_wrap_p)
> > [...]
> > @@ -1066,11 +1077,17 @@ vect_verify_full_masking (loop_vec_info loop_vinfo)
> > if (this_type
> > && can_produce_all_loop_masks_p (loop_vinfo, this_type))
> > {
> > - /* Although we could stop as soon as we find a valid mode,
> > - it's often better to continue until we hit Pmode, since the
> > + /* See whether zero-based IV would ever generate all-false masks
> > + before wrapping around. */
> > + bool might_wrap_p = (iv_precision > cmp_bits);
> > + /* Stop as soon as we find a valid mode. If we decided to use
> > + cmp_type which is less than Pmode precision, it is often
> > better
> > + to use iv_type corresponding to Pmode, since the
> > operands to the WHILE are more likely to be reusable in
> > - address calculations. */
> > - cmp_type = this_type;
> > + address calculations in this case. */
>
> We're not stopping as soon as we find a valid mode though. Any type
> that satisfies the if condition above is valid, but we pick wider
> cmp_types and iv_types for optimisation reasons. How about:
>
> /* Although we could stop as soon as we find a valid mode,
> there are at least two reasons why that's not always the
> best choice:
>
> - An IV that's Pmode or wider is more likely to be reusable
> in address calculations than an IV that's narrower than
> Pmode.
>
> - Doing the comparison in IV_PRECISION or wider allows
> a natural 0-based IV, whereas using a narrower comparison
> type requires mitigations against wrap-around.
>
> Conversely, if the IV limit is variable, doing the comparison
> in a wider type than the original type can introduce
> unnecessary extensions, so picking the widest valid mode
> is not always a good choice either.
>
> Here we prefer the first IV type that's Pmode or wider,
> and the first comparison type that's IV_PRECISION or wider.
> (The comparison type must be no wider than the IV type,
> to avoid extensions in the vector loop.)
>
> ??? We might want to try continuing beyond Pmode for ILP32
> targets if CMP_BITS < IV_PRECISION. */
>
> > + iv_type = this_type;
> > + if (!cmp_type || iv_precision > TYPE_PRECISION (cmp_type))
> > + cmp_type = this_type;
> > if (cmp_bits >= GET_MODE_BITSIZE (Pmode))
> > break;
> > }
>
> > [...]
> > @@ -9014,3 +9032,45 @@ optimize_mask_stores (struct loop *loop)
> > add_phi_arg (phi, gimple_vuse (last_store), e, UNKNOWN_LOCATION);
> > }
> > }
> > +
> > +/* Decide whether it is possible to use a zero-based induction variable
> > + when vectorizing LOOP_VINFO with a fully-masked loop. If it is,
> > + return the value that the induction variable must be able to hold
> > + in order to ensure that the loop ends with an all-false mask.
> > + Return -1 otherwise. */
> > +widest_int
> > +vect_iv_limit_for_full_masking (loop_vec_info loop_vinfo)
> > +{
> > + tree niters_skip = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
> > + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
> > + unsigned HOST_WIDE_INT max_vf = vect_max_vf (loop_vinfo);
> > +
> > + /* Now calculate the value that the induction variable must be able
>
> s/Now calculate/Calculate/
>
> since this comment is no longer following on from earlier code.
>
> OK with those changes, thanks.
>
> Richard
From 3195876b6424ce0e079afad9437e96abba3b45c1 Mon Sep 17 00:00:00 2001
From: Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org>
Date: Tue, 28 May 2019 11:57:54 +1000
Subject: [PATCH] PR88838 V5
Change-Id: Icaa9658359b9b71e0148ff5f9d4a14b6bb8df05a
---
gcc/fwprop.c | 9 +++
gcc/testsuite/gcc.target/aarch64/pr88838.c | 11 ++++
gcc/testsuite/gcc.target/aarch64/sve/while_1.c | 16 ++---
gcc/tree-vect-loop-manip.c | 46 +++++---------
gcc/tree-vect-loop.c | 85 ++++++++++++++++++++++++--
gcc/tree-vectorizer.h | 6 ++
6 files changed, 129 insertions(+), 44 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/pr88838.c
diff --git a/gcc/fwprop.c b/gcc/fwprop.c
index cf2c9de..2c99285 100644
--- a/gcc/fwprop.c
+++ b/gcc/fwprop.c
@@ -1358,6 +1358,15 @@ forward_propagate_and_simplify (df_ref use, rtx_insn *def_insn, rtx def_set)
else
mode = GET_MODE (*loc);
+ /* TODO. We can't get the mode for
+ (set (reg:VNx16BI 109)
+ (unspec:VNx16BI [
+ (reg:SI 131)
+ (reg:SI 106)
+ ] UNSPEC_WHILE_LO))
+ Thus, bailout when it is UNSPEC and MODEs are not compatible. */
+ if (GET_MODE_CLASS (mode) != GET_MODE_CLASS (GET_MODE (reg)))
+ return false;
new_rtx = propagate_rtx (*loc, mode, reg, src,
optimize_bb_for_speed_p (BLOCK_FOR_INSN (use_insn)));
diff --git a/gcc/testsuite/gcc.target/aarch64/pr88838.c b/gcc/testsuite/gcc.target/aarch64/pr88838.c
new file mode 100644
index 0000000..d7db847
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr88838.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-S -O3 -march=armv8.2-a+sve" } */
+
+void
+f (int *restrict x, int *restrict y, int *restrict z, int n)
+{
+ for (int i = 0; i < n; i += 1)
+ x[i] = y[i] + z[i];
+}
+
+/* { dg-final { scan-assembler-not "sxtw" } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/while_1.c b/gcc/testsuite/gcc.target/aarch64/sve/while_1.c
index a93a04b..05a4860 100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/while_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/while_1.c
@@ -26,14 +26,14 @@
TEST_ALL (ADD_LOOP)
/* { dg-final { scan-assembler-not {\tuqdec} } } */
-/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.b, xzr,} 2 } } */
-/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.b, x[0-9]+,} 2 } } */
-/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.h, xzr,} 2 } } */
-/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.h, x[0-9]+,} 2 } } */
-/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.s, xzr,} 3 } } */
-/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.s, x[0-9]+,} 3 } } */
-/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.d, xzr,} 3 } } */
-/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.d, x[0-9]+,} 3 } } */
+/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.b, wzr,} 2 } } */
+/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.b, w[0-9]+,} 2 } } */
+/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.h, wzr,} 2 } } */
+/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.h, w[0-9]+,} 2 } } */
+/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.s, wzr,} 3 } } */
+/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.s, w[0-9]+,} 3 } } */
+/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.d, wzr,} 3 } } */
+/* { dg-final { scan-assembler-times {\twhilelo\tp[0-7]\.d, w[0-9]+,} 3 } } */
/* { dg-final { scan-assembler-times {\tld1b\tz[0-9]+\.b, p[0-7]/z, \[x0, x[0-9]+\]\n} 2 } } */
/* { dg-final { scan-assembler-times {\tst1b\tz[0-9]+\.b, p[0-7], \[x0, x[0-9]+\]\n} 2 } } */
/* { dg-final { scan-assembler-times {\tld1h\tz[0-9]+\.h, p[0-7]/z, \[x0, x[0-9]+, lsl 1\]\n} 2 } } */
diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
index b3fae5b..a0a1bee 100644
--- a/gcc/tree-vect-loop-manip.c
+++ b/gcc/tree-vect-loop-manip.c
@@ -415,6 +415,7 @@ vect_set_loop_masks_directly (struct loop *loop, loop_vec_info loop_vinfo,
bool might_wrap_p)
{
tree compare_type = LOOP_VINFO_MASK_COMPARE_TYPE (loop_vinfo);
+ tree iv_type = LOOP_VINFO_MASK_IV_TYPE (loop_vinfo);
tree mask_type = rgm->mask_type;
unsigned int nscalars_per_iter = rgm->max_nscalars_per_iter;
poly_uint64 nscalars_per_mask = TYPE_VECTOR_SUBPARTS (mask_type);
@@ -445,11 +446,16 @@ vect_set_loop_masks_directly (struct loop *loop, loop_vec_info loop_vinfo,
tree index_before_incr, index_after_incr;
gimple_stmt_iterator incr_gsi;
bool insert_after;
- tree zero_index = build_int_cst (compare_type, 0);
standard_iv_increment_position (loop, &incr_gsi, &insert_after);
- create_iv (zero_index, nscalars_step, NULL_TREE, loop, &incr_gsi,
+
+ tree zero_index = build_int_cst (iv_type, 0);
+ tree step = build_int_cst (iv_type,
+ LOOP_VINFO_VECT_FACTOR (loop_vinfo));
+ /* Create IV of iv_type. */
+ create_iv (zero_index, step, NULL_TREE, loop, &incr_gsi,
insert_after, &index_before_incr, &index_after_incr);
+ zero_index = build_int_cst (compare_type, 0);
tree test_index, test_limit, first_limit;
gimple_stmt_iterator *test_gsi;
if (might_wrap_p)
@@ -529,6 +535,10 @@ vect_set_loop_masks_directly (struct loop *loop, loop_vec_info loop_vinfo,
tree next_mask = NULL_TREE;
tree mask;
unsigned int i;
+ gimple_seq test_seq = NULL;
+ test_index = gimple_convert (&test_seq, compare_type, test_index);
+ gsi_insert_seq_before (test_gsi, test_seq, GSI_SAME_STMT);
+
FOR_EACH_VEC_ELT_REVERSE (rgm->masks, i, mask)
{
/* Previous masks will cover BIAS scalars. This mask covers the
@@ -637,12 +647,12 @@ vect_set_loop_condition_masked (struct loop *loop, loop_vec_info loop_vinfo,
tree compare_type = LOOP_VINFO_MASK_COMPARE_TYPE (loop_vinfo);
unsigned int compare_precision = TYPE_PRECISION (compare_type);
- unsigned HOST_WIDE_INT max_vf = vect_max_vf (loop_vinfo);
tree orig_niters = niters;
/* Type of the initial value of NITERS. */
tree ni_actual_type = TREE_TYPE (niters);
unsigned int ni_actual_precision = TYPE_PRECISION (ni_actual_type);
+ tree niters_skip = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
/* Convert NITERS to the same size as the compare. */
if (compare_precision > ni_actual_precision
@@ -661,33 +671,7 @@ vect_set_loop_condition_masked (struct loop *loop, loop_vec_info loop_vinfo,
else
niters = gimple_convert (&preheader_seq, compare_type, niters);
- /* Convert skip_niters to the right type. */
- tree niters_skip = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
-
- /* Now calculate the value that the induction variable must be able
- to hit in order to ensure that we end the loop with an all-false mask.
- This involves adding the maximum number of inactive trailing scalar
- iterations. */
- widest_int iv_limit;
- bool known_max_iters = max_loop_iterations (loop, &iv_limit);
- if (known_max_iters)
- {
- if (niters_skip)
- {
- /* Add the maximum number of skipped iterations to the
- maximum iteration count. */
- if (TREE_CODE (niters_skip) == INTEGER_CST)
- iv_limit += wi::to_widest (niters_skip);
- else
- iv_limit += max_vf - 1;
- }
- /* IV_LIMIT is the maximum number of latch iterations, which is also
- the maximum in-range IV value. Round this value down to the previous
- vector alignment boundary and then add an extra full iteration. */
- poly_uint64 vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
- iv_limit = (iv_limit & -(int) known_alignment (vf)) + max_vf;
- }
-
+ widest_int iv_limit = vect_iv_limit_for_full_masking (loop_vinfo);
/* Get the vectorization factor in tree form. */
tree vf = build_int_cst (compare_type,
LOOP_VINFO_VECT_FACTOR (loop_vinfo));
@@ -717,7 +701,7 @@ vect_set_loop_condition_masked (struct loop *loop, loop_vec_info loop_vinfo,
/* See whether zero-based IV would ever generate all-false masks
before wrapping around. */
bool might_wrap_p
- = (!known_max_iters
+ = (iv_limit == -1
|| (wi::min_precision (iv_limit * rgm->max_nscalars_per_iter,
UNSIGNED)
> compare_precision));
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 4942c69..671ef2f 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -1030,6 +1030,8 @@ vect_verify_full_masking (loop_vec_info loop_vinfo)
{
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
unsigned int min_ni_width;
+ unsigned int max_nscalars_per_iter
+ = vect_get_max_nscalars_per_iter (loop_vinfo);
/* Use a normal loop if there are no statements that need masking.
This only happens in rare degenerate cases: it means that the loop
@@ -1048,7 +1050,7 @@ vect_verify_full_masking (loop_vec_info loop_vinfo)
max_ni = wi::smin (max_ni, max_back_edges + 1);
/* Account for rgroup masks, in which each bit is replicated N times. */
- max_ni *= vect_get_max_nscalars_per_iter (loop_vinfo);
+ max_ni *= max_nscalars_per_iter;
/* Work out how many bits we need to represent the limit. */
min_ni_width = wi::min_precision (max_ni, UNSIGNED);
@@ -1056,6 +1058,14 @@ vect_verify_full_masking (loop_vec_info loop_vinfo)
/* Find a scalar mode for which WHILE_ULT is supported. */
opt_scalar_int_mode cmp_mode_iter;
tree cmp_type = NULL_TREE;
+ tree iv_type = NULL_TREE;
+ widest_int iv_limit = vect_iv_limit_for_full_masking (loop_vinfo);
+ widest_int iv_precision = UINT_MAX;
+
+ if (iv_limit != -1)
+ iv_precision = wi::min_precision (iv_limit * max_nscalars_per_iter,
+ UNSIGNED);
+
FOR_EACH_MODE_IN_CLASS (cmp_mode_iter, MODE_INT)
{
unsigned int cmp_bits = GET_MODE_BITSIZE (cmp_mode_iter.require ());
@@ -1067,10 +1077,32 @@ vect_verify_full_masking (loop_vec_info loop_vinfo)
&& can_produce_all_loop_masks_p (loop_vinfo, this_type))
{
/* Although we could stop as soon as we find a valid mode,
- it's often better to continue until we hit Pmode, since the
- operands to the WHILE are more likely to be reusable in
- address calculations. */
- cmp_type = this_type;
+ there are at least two reasons why that's not always the
+ best choice:
+
+ - An IV that's Pmode or wider is more likely to be reusable
+ in address calculations than an IV that's narrower than
+ Pmode.
+
+ - Doing the comparison in IV_PRECISION or wider allows
+ a natural 0-based IV, whereas using a narrower comparison
+ type requires mitigations against wrap-around.
+
+ Conversely, if the IV limit is variable, doing the comparison
+ in a wider type than the original type can introduce
+ unnecessary extensions, so picking the widest valid mode
+ is not always a good choice either.
+
+ Here we prefer the first IV type that's Pmode or wider,
+ and the first comparison type that's IV_PRECISION or wider.
+ (The comparison type must be no wider than the IV type,
+ to avoid extensions in the vector loop.)
+
+ ??? We might want to try continuing beyond Pmode for ILP32
+ targets if CMP_BITS < IV_PRECISION. */
+ iv_type = this_type;
+ if (!cmp_type || iv_precision > TYPE_PRECISION (cmp_type))
+ cmp_type = this_type;
if (cmp_bits >= GET_MODE_BITSIZE (Pmode))
break;
}
@@ -1081,6 +1113,7 @@ vect_verify_full_masking (loop_vec_info loop_vinfo)
return false;
LOOP_VINFO_MASK_COMPARE_TYPE (loop_vinfo) = cmp_type;
+ LOOP_VINFO_MASK_IV_TYPE (loop_vinfo) = iv_type;
return true;
}
@@ -9014,3 +9047,45 @@ optimize_mask_stores (struct loop *loop)
add_phi_arg (phi, gimple_vuse (last_store), e, UNKNOWN_LOCATION);
}
}
+
+/* Decide whether it is possible to use a zero-based induction variable
+ when vectorizing LOOP_VINFO with a fully-masked loop. If it is,
+ return the value that the induction variable must be able to hold
+ in order to ensure that the loop ends with an all-false mask.
+ Return -1 otherwise. */
+widest_int
+vect_iv_limit_for_full_masking (loop_vec_info loop_vinfo)
+{
+ tree niters_skip = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
+ struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+ unsigned HOST_WIDE_INT max_vf = vect_max_vf (loop_vinfo);
+
+ /* Calculate the value that the induction variable must be able
+ to hit in order to ensure that we end the loop with an all-false mask.
+ This involves adding the maximum number of inactive trailing scalar
+ iterations. */
+ widest_int iv_limit = -1;
+ if (max_loop_iterations (loop, &iv_limit))
+ {
+ if (niters_skip)
+ {
+ /* Add the maximum number of skipped iterations to the
+ maximum iteration count. */
+ if (TREE_CODE (niters_skip) == INTEGER_CST)
+ iv_limit += wi::to_widest (niters_skip);
+ else
+ iv_limit += max_vf - 1;
+ }
+ else if (LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo))
+ /* Make a conservatively-correct assumption. */
+ iv_limit += max_vf - 1;
+
+ /* IV_LIMIT is the maximum number of latch iterations, which is also
+ the maximum in-range IV value. Round this value down to the previous
+ vector alignment boundary and then add an extra full iteration. */
+ poly_uint64 vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
+ iv_limit = (iv_limit & -(int) known_alignment (vf)) + max_vf;
+ }
+ return iv_limit;
+}
+
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 4db30cc..eb0f21f 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -435,6 +435,10 @@ typedef struct _loop_vec_info : public vec_info {
is false and vectorized loop otherwise. */
tree simd_if_cond;
+ /* Type of the IV to use in the WHILE_ULT call for fully-masked
+ loops. */
+ tree iv_type;
+
/* Unknown DRs according to which loop was peeled. */
struct dr_vec_info *unaligned_dr;
@@ -570,6 +574,7 @@ typedef struct _loop_vec_info : public vec_info {
#define LOOP_VINFO_MASKS(L) (L)->masks
#define LOOP_VINFO_MASK_SKIP_NITERS(L) (L)->mask_skip_niters
#define LOOP_VINFO_MASK_COMPARE_TYPE(L) (L)->mask_compare_type
+#define LOOP_VINFO_MASK_IV_TYPE(L) (L)->iv_type
#define LOOP_VINFO_PTR_MASK(L) (L)->ptr_mask
#define LOOP_VINFO_LOOP_NEST(L) (L)->shared->loop_nest
#define LOOP_VINFO_DATAREFS(L) (L)->shared->datarefs
@@ -1582,6 +1587,7 @@ extern tree vect_create_addr_base_for_vector_ref (stmt_vec_info, gimple_seq *,
/* FORNOW: Used in tree-parloops.c. */
extern stmt_vec_info vect_force_simple_reduction (loop_vec_info, stmt_vec_info,
bool *, bool);
+extern widest_int vect_iv_limit_for_full_masking (loop_vec_info loop_vinfo);
/* Used in gimple-loop-interchange.c. */
extern bool check_reduction_path (dump_user_location_t, loop_p, gphi *, tree,
enum tree_code);
--
2.7.4
