This removes the canonicalization of X + -CST to X - CST to facilitate
SLP vectorization analysis where we currently treat the added testcase
as two-operation plus blend vectorization opportunity. While there
may be the possibility to avoid this in the vectorizer itself the
canonicalization is somewhat premature - it's motivation is that
a FP constant of both signs is common and thus canonicalizing to
positive values optimizes constant pool. But if you mix, say,
x * -7.1 and x - 7.1 this backfires - this instead looks like
a local optimization to be applied in RTL CSE or even LRA
load inheritance. I filed PR97071 for this.
Bootstrapped and tested on x86_64-unknown-linux-gnu, any objections?
Thanks,
Richard.
2020-09-16 Richard Biener <rguent...@suse.de>
* fold-const.c (fold_binary_loc): Remove condition
on REAL_CST for A - B -> A + (-B) transform.
(negate_expr_p): Remove condition on REAL_CST.
* match.pd (negate_expr_p): Likewise.
(X + -C -> X - C): Remove.
* gcc.dg/vect/slp-49.c: New testcase.
* gcc.dg/tree-ssa/pr90356-1.c: Adjust.
* gcc.dg/tree-ssa/pr90356-3.c: Likewise.
* gcc.dg/tree-ssa/pr90356-4.c: Likewise.
* gcc.target/i386/pr54855-3.c: Likewise.
* gfortran.dg/reassoc_1.f90: Likewise.
* gfortran.dg/reassoc_2.f90: Likewise.
---
gcc/fold-const.c | 7 ++-----
gcc/match.pd | 11 +----------
gcc/testsuite/gcc.dg/tree-ssa/pr90356-1.c | 4 ++--
gcc/testsuite/gcc.dg/tree-ssa/pr90356-3.c | 2 +-
gcc/testsuite/gcc.dg/tree-ssa/pr90356-4.c | 2 +-
gcc/testsuite/gcc.dg/vect/slp-49.c | 15 +++++++++++++++
gcc/testsuite/gcc.target/i386/pr54855-3.c | 2 +-
gcc/testsuite/gfortran.dg/reassoc_1.f90 | 2 +-
gcc/testsuite/gfortran.dg/reassoc_2.f90 | 2 +-
9 files changed, 25 insertions(+), 22 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/vect/slp-49.c
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 0cc80adf632..ec369169a4c 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -401,7 +401,7 @@ negate_expr_p (tree t)
case REAL_CST:
/* We want to canonicalize to positive real constants. Pretend
that only negative ones can be easily negated. */
- return REAL_VALUE_NEGATIVE (TREE_REAL_CST (t));
+ return true;
case COMPLEX_CST:
return negate_expr_p (TREE_REALPART (t))
@@ -10962,10 +10962,7 @@ fold_binary_loc (location_t loc, enum tree_code code,
tree type,
/* A - B -> A + (-B) if B is easily negatable. */
if (negate_expr_p (op1)
&& ! TYPE_OVERFLOW_SANITIZED (type)
- && ((FLOAT_TYPE_P (type)
- /* Avoid this transformation if B is a positive REAL_CST. */
- && (TREE_CODE (op1) != REAL_CST
- || REAL_VALUE_NEGATIVE (TREE_REAL_CST (op1))))
+ && (FLOAT_TYPE_P (type)
|| INTEGRAL_TYPE_P (type)))
return fold_build2_loc (loc, PLUS_EXPR, type,
fold_convert_loc (loc, type, arg0),
diff --git a/gcc/match.pd b/gcc/match.pd
index 7d63bb973cb..9f14d50ae2d 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1307,8 +1307,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(negate @0)
(if (!TYPE_OVERFLOW_SANITIZED (type))))
(match negate_expr_p
- REAL_CST
- (if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (t)))))
+ REAL_CST)
/* VECTOR_CST handling of non-wrapping types would recurse in unsupported
ways. */
(match negate_expr_p
@@ -3326,14 +3325,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* Canonicalization of binary operations. */
-/* Convert X + -C into X - C. */
-(simplify
- (plus @0 REAL_CST@1)
- (if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (@1)))
- (with { tree tem = const_unop (NEGATE_EXPR, type, @1); }
- (if (!TREE_OVERFLOW (tem) || !flag_trapping_math)
- (minus @0 { tem; })))))
-
/* Convert x+x into x*2. */
(simplify
(plus @0 @0)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr90356-1.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr90356-1.c
index c3a15ea21af..ac95ec56810 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr90356-1.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr90356-1.c
@@ -2,8 +2,8 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-rounding-math -fsignaling-nans -fsigned-zeros
-fdump-tree-optimized" } */
/* { dg-final { scan-tree-dump-times "x_\[0-9]*.D. \\+ 0.0;" 12 "optimized" }
} */
-/* { dg-final { scan-tree-dump-times "y_\[0-9]*.D. - 0.0;" 4 "optimized" } } */
-/* { dg-final { scan-tree-dump-times " \[+-] 0.0;" 16 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "y_\[0-9]*.D. \\+ -0.0;" 4 "optimized" }
} */
+/* { dg-final { scan-tree-dump-times " \\+ -?0.0;" 16 "optimized" } } */
double f1 (double x) { return (x + 0.0) + 0.0; }
double f2 (double y) { return (y + (-0.0)) + (-0.0); }
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr90356-3.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr90356-3.c
index e658130c69f..951971b95ee 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr90356-3.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr90356-3.c
@@ -1,6 +1,6 @@
/* PR tree-optimization/90356 */
/* { dg-do compile } */
/* { dg-options "-O2 -frounding-math -fsignaling-nans -fsigned-zeros
-fdump-tree-optimized" } */
-/* { dg-final { scan-tree-dump-times " \[+-] 0.0;" 32 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " \\+ -?0.0;" 32 "optimized" } } */
#include "pr90356-1.c"
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr90356-4.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr90356-4.c
index 126cd10928b..3459ddba356 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr90356-4.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr90356-4.c
@@ -1,6 +1,6 @@
/* PR tree-optimization/90356 */
/* { dg-do compile } */
/* { dg-options "-O2 -frounding-math -fno-signaling-nans -fsigned-zeros
-fdump-tree-optimized" } */
-/* { dg-final { scan-tree-dump-times " \[+-] 0.0;" 32 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " \\+ -?0.0;" 32 "optimized" } } */
#include "pr90356-1.c"
diff --git a/gcc/testsuite/gcc.dg/vect/slp-49.c
b/gcc/testsuite/gcc.dg/vect/slp-49.c
new file mode 100644
index 00000000000..4b3ec77b99d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/slp-49.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_double } */
+
+void foo (double *x)
+{
+ for (int i = 0; i < 1024; ++i)
+ {
+ x[2*i] += 1.0;
+ x[2*i+1] -= 2.0;
+ }
+}
+
+/* { dg-final { scan-tree-dump "loop vectorized" "vect" } } */
+/* The loop should be SLPed with uniform plus. */
+/* { dg-final { scan-tree-dump-not "VEC_PERM" "vect" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr54855-3.c
b/gcc/testsuite/gcc.target/i386/pr54855-3.c
index 3c15dfc93d1..802d6882e43 100644
--- a/gcc/testsuite/gcc.target/i386/pr54855-3.c
+++ b/gcc/testsuite/gcc.target/i386/pr54855-3.c
@@ -1,6 +1,6 @@
/* { dg-do compile } */
/* { dg-options "-O2 -msse2 -mfpmath=sse" } */
-/* { dg-final { scan-assembler-times "subsd" 1 } } */
+/* { dg-final { scan-assembler-times "addsd" 1 } } */
/* { dg-final { scan-assembler-not "movapd" } } */
/* { dg-final { scan-assembler-not "movsd" } } */
diff --git a/gcc/testsuite/gfortran.dg/reassoc_1.f90
b/gcc/testsuite/gfortran.dg/reassoc_1.f90
index e3d84c4ffd9..19b47fc7ce6 100644
--- a/gcc/testsuite/gfortran.dg/reassoc_1.f90
+++ b/gcc/testsuite/gfortran.dg/reassoc_1.f90
@@ -9,4 +9,4 @@ end
! We need an explicit +5 and -5, and an intermediate ((bla)) expression
! (the reassoc barrier). Make use of "." matching lineends.
-! { dg-final { scan-tree-dump "\\\+ 5.*\\\)\\\).* - 5" "optimized" } }
+! { dg-final { scan-tree-dump "\\\+ 5.*\\\)\\\).* \\\+ -5" "optimized" } }
diff --git a/gcc/testsuite/gfortran.dg/reassoc_2.f90
b/gcc/testsuite/gfortran.dg/reassoc_2.f90
index 3e323eb0134..62361619932 100644
--- a/gcc/testsuite/gfortran.dg/reassoc_2.f90
+++ b/gcc/testsuite/gfortran.dg/reassoc_2.f90
@@ -12,4 +12,4 @@ function test(a)
test = d
end
-! { dg-final { scan-tree-dump "- 5" "optimized" } }
+! { dg-final { scan-tree-dump "\\\+ -5" "optimized" } }
--
2.26.2
