>So the bugs were not fixed without this hunk? IIRC in the audit
>trail we concluded the value is always positive ... (but of course
>a large unsigned value can appear negative if you test it this way?)
No, I added this incase in the future there's negative skip_niters as
you mentioned in the PR, it's just defensive programming.
>I think you can use one of the mpz_pow* functions and
>wi::to_mpz/from_mpz for this. See tree-ssa-loop-niter.cc for the
>most heavy user of mpz (but not pow I think).
Changed.
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk.
There's loop in vect_peel_nonlinear_iv_init to get init_expr *
pow (step_expr, skip_niters). When skipn_iters is too big, compile time
hogs. To avoid that, optimize init_expr * pow (step_expr, skip_niters) to
init_expr << (exact_log2 (step_expr) * skip_niters) when step_expr is
pow of 2, otherwise give up vectorization when skip_niters >=
TYPE_PRECISION (TREE_TYPE (init_expr)).
Also give up vectorization when niters_skip is negative which will be
used for fully masked loop.
gcc/ChangeLog:
PR tree-optimization/111820
PR tree-optimization/111833
* tree-vect-loop-manip.cc (vect_can_peel_nonlinear_iv_p): Give
up vectorization for nonlinear iv vect_step_op_mul when
step_expr is not exact_log2 and niters is greater than
TYPE_PRECISION (TREE_TYPE (step_expr)). Also don't vectorize
for nagative niters_skip which will be used by fully masked
loop.
(vect_can_advance_ivs_p): Pass whole phi_info to
vect_can_peel_nonlinear_iv_p.
* tree-vect-loop.cc (vect_peel_nonlinear_iv_init): Optimize
init_expr * pow (step_expr, skipn) to init_expr
<< (log2 (step_expr) * skipn) when step_expr is exact_log2.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr111820-1.c: New test.
* gcc.target/i386/pr111820-2.c: New test.
* gcc.target/i386/pr111820-3.c: New test.
* gcc.target/i386/pr103144-mul-1.c: Adjust testcase.
* gcc.target/i386/pr103144-mul-2.c: Adjust testcase.
---
.../gcc.target/i386/pr103144-mul-1.c | 8 ++---
.../gcc.target/i386/pr103144-mul-2.c | 8 ++---
gcc/testsuite/gcc.target/i386/pr111820-1.c | 16 +++++++++
gcc/testsuite/gcc.target/i386/pr111820-2.c | 16 +++++++++
gcc/testsuite/gcc.target/i386/pr111820-3.c | 16 +++++++++
gcc/tree-vect-loop-manip.cc | 28 +++++++++++++--
gcc/tree-vect-loop.cc | 34 ++++++++++++++++---
7 files changed, 110 insertions(+), 16 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr111820-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr111820-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr111820-3.c
diff --git a/gcc/testsuite/gcc.target/i386/pr103144-mul-1.c
b/gcc/testsuite/gcc.target/i386/pr103144-mul-1.c
index 640c34fd959..913d7737dcd 100644
--- a/gcc/testsuite/gcc.target/i386/pr103144-mul-1.c
+++ b/gcc/testsuite/gcc.target/i386/pr103144-mul-1.c
@@ -11,7 +11,7 @@ foo_mul (int* a, int b)
for (int i = 0; i != N; i++)
{
a[i] = b;
- b *= 3;
+ b *= 4;
}
}
@@ -23,7 +23,7 @@ foo_mul_const (int* a)
for (int i = 0; i != N; i++)
{
a[i] = b;
- b *= 3;
+ b *= 4;
}
}
@@ -34,7 +34,7 @@ foo_mul_peel (int* a, int b)
for (int i = 0; i != 39; i++)
{
a[i] = b;
- b *= 3;
+ b *= 4;
}
}
@@ -46,6 +46,6 @@ foo_mul_peel_const (int* a)
for (int i = 0; i != 39; i++)
{
a[i] = b;
- b *= 3;
+ b *= 4;
}
}
diff --git a/gcc/testsuite/gcc.target/i386/pr103144-mul-2.c
b/gcc/testsuite/gcc.target/i386/pr103144-mul-2.c
index 39fdea3a69d..b2ff186e335 100644
--- a/gcc/testsuite/gcc.target/i386/pr103144-mul-2.c
+++ b/gcc/testsuite/gcc.target/i386/pr103144-mul-2.c
@@ -16,12 +16,12 @@ avx2_test (void)
__builtin_memset (epi32_exp, 0, N * sizeof (int));
int b = 8;
- v8si init = __extension__(v8si) { b, b * 3, b * 9, b * 27, b * 81, b * 243,
b * 729, b * 2187 };
+ v8si init = __extension__(v8si) { b, b * 4, b * 16, b * 64, b * 256, b *
1024, b * 4096, b * 16384 };
for (int i = 0; i != N / 8; i++)
{
memcpy (epi32_exp + i * 8, &init, 32);
- init *= 6561;
+ init *= 65536;
}
foo_mul (epi32_dst, b);
@@ -32,11 +32,11 @@ avx2_test (void)
if (__builtin_memcmp (epi32_dst, epi32_exp, 39 * 4) != 0)
__builtin_abort ();
- init = __extension__(v8si) { 1, 3, 9, 27, 81, 243, 729, 2187 };
+ init = __extension__(v8si) { 1, 4, 16, 64, 256, 1024, 4096, 16384 };
for (int i = 0; i != N / 8; i++)
{
memcpy (epi32_exp + i * 8, &init, 32);
- init *= 6561;
+ init *= 65536;
}
foo_mul_const (epi32_dst);
diff --git a/gcc/testsuite/gcc.target/i386/pr111820-1.c
b/gcc/testsuite/gcc.target/i386/pr111820-1.c
new file mode 100644
index 00000000000..50e960c39d4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr111820-1.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -mavx2 -fno-tree-vrp -Wno-aggressive-loop-optimizations
-fdump-tree-vect-details" } */
+/* { dg-final { scan-tree-dump "Avoid compile time hog on
vect_peel_nonlinear_iv_init for nonlinear induction vec_step_op_mul when
iteration count is too big" "vect" } } */
+
+int r;
+int r_0;
+
+void f1 (void)
+{
+ int n = 0;
+ while (-- n)
+ {
+ r_0 += r;
+ r *= 3;
+ }
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr111820-2.c
b/gcc/testsuite/gcc.target/i386/pr111820-2.c
new file mode 100644
index 00000000000..dbeceb228c3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr111820-2.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -mavx2 -fno-tree-vrp -fdump-tree-vect-details
-Wno-aggressive-loop-optimizations" } */
+/* { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" } } */
+
+int r;
+int r_0;
+
+void f (void)
+{
+ int n = 0;
+ while (-- n)
+ {
+ r_0 += r ;
+ r *= 2;
+ }
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr111820-3.c
b/gcc/testsuite/gcc.target/i386/pr111820-3.c
new file mode 100644
index 00000000000..b778f517663
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr111820-3.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -mavx2 -fno-tree-vrp -fdump-tree-vect-details
-Wno-aggressive-loop-optimizations" } */
+/* { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" } } */
+
+int r;
+int r_0;
+
+void f (void)
+{
+ int n = 14;
+ while (-- n)
+ {
+ r_0 += r ;
+ r *= 3;
+ }
+}
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index 2608c286e5d..a530088b61d 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -1783,8 +1783,10 @@ iv_phi_p (stmt_vec_info stmt_info)
/* Return true if vectorizer can peel for nonlinear iv. */
static bool
vect_can_peel_nonlinear_iv_p (loop_vec_info loop_vinfo,
- enum vect_induction_op_type induction_type)
+ stmt_vec_info stmt_info)
{
+ enum vect_induction_op_type induction_type
+ = STMT_VINFO_LOOP_PHI_EVOLUTION_TYPE (stmt_info);
tree niters_skip;
/* Init_expr will be update by vect_update_ivs_after_vectorizer,
if niters or vf is unkown:
@@ -1805,11 +1807,31 @@ vect_can_peel_nonlinear_iv_p (loop_vec_info loop_vinfo,
return false;
}
+ /* Avoid compile time hog on vect_peel_nonlinear_iv_init. */
+ if (induction_type == vect_step_op_mul)
+ {
+ tree step_expr = STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_info);
+ tree type = TREE_TYPE (step_expr);
+
+ if (wi::exact_log2 (wi::to_wide (step_expr)) == -1
+ && LOOP_VINFO_INT_NITERS(loop_vinfo) >= TYPE_PRECISION (type))
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+ "Avoid compile time hog on"
+ " vect_peel_nonlinear_iv_init"
+ " for nonlinear induction vec_step_op_mul"
+ " when iteration count is too big.\n");
+ return false;
+ }
+ }
+
/* Also doens't support peel for neg when niter is variable.
??? generate something like niter_expr & 1 ? init_expr : -init_expr? */
niters_skip = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
if ((niters_skip != NULL_TREE
- && TREE_CODE (niters_skip) != INTEGER_CST)
+ && (TREE_CODE (niters_skip) != INTEGER_CST
+ || (HOST_WIDE_INT) TREE_INT_CST_LOW (niters_skip) < 0))
|| (!vect_use_loop_mask_for_alignment_p (loop_vinfo)
&& LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo) < 0))
{
@@ -1870,7 +1892,7 @@ vect_can_advance_ivs_p (loop_vec_info loop_vinfo)
induction_type = STMT_VINFO_LOOP_PHI_EVOLUTION_TYPE (phi_info);
if (induction_type != vect_step_op_add)
{
- if (!vect_can_peel_nonlinear_iv_p (loop_vinfo, induction_type))
+ if (!vect_can_peel_nonlinear_iv_p (loop_vinfo, phi_info))
return false;
continue;
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 89bdcaa0910..f0dbba50786 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -9134,11 +9134,35 @@ vect_peel_nonlinear_iv_init (gimple_seq* stmts, tree
init_expr,
init_expr = gimple_convert (stmts, utype, init_expr);
unsigned skipn = TREE_INT_CST_LOW (skip_niters);
wide_int begin = wi::to_wide (step_expr);
- for (unsigned i = 0; i != skipn - 1; i++)
- begin = wi::mul (begin, wi::to_wide (step_expr));
- tree mult_expr = wide_int_to_tree (utype, begin);
- init_expr = gimple_build (stmts, MULT_EXPR, utype, init_expr,
mult_expr);
- init_expr = gimple_convert (stmts, type, init_expr);
+ int pow2_step = wi::exact_log2 (begin);
+ /* Optimize init_expr * pow (step_expr, skipn) to
+ init_expr << (log2 (step_expr) * skipn). */
+ if (pow2_step != -1)
+ {
+ if (skipn >= TYPE_PRECISION (type)
+ || skipn > (UINT_MAX / (unsigned) pow2_step)
+ || skipn * (unsigned) pow2_step >= TYPE_PRECISION (type))
+ init_expr = build_zero_cst (type);
+ else
+ {
+ tree lshc = build_int_cst (utype, skipn * (unsigned) pow2_step);
+ init_expr = gimple_build (stmts, LSHIFT_EXPR, utype,
+ init_expr, lshc);
+ }
+ }
+ /* Any better way for init_expr * pow (step_expr, skipn)???. */
+ else
+ {
+ gcc_assert (skipn < TYPE_PRECISION (type));
+ auto_mpz base, exp;
+ wi::to_mpz (begin, base, TYPE_SIGN (type));
+ mpz_pow_ui (exp, base, skipn);
+ begin = wi::from_mpz (type, exp, TYPE_SIGN (type));
+ tree mult_expr = wide_int_to_tree (utype, begin);
+ init_expr = gimple_build (stmts, MULT_EXPR, utype,
+ init_expr, mult_expr);
+ }
+ init_expr = gimple_convert (stmts, type, init_expr);
}
break;
--
2.31.1
