middle-end: Don't apply copysign optimization if target does not implement optab...

Currently GCC does not treat IFN_COPYSIGN the same as the copysign tree expr.
The latter has a libcall fallback and the IFN can only do optabs.

Because of this the change I made to optimize copysign only works if the
target has impemented the optab, but it should work for those that have the
libcall too.

More annoyingly if a target has vector versions of ABS and NEG but not COPYSIGN
then the change made them lose vectorization.

The proper fix for this is to treat the IFN the same as the tree EXPR and to
enhance expand_COPYSIGN to also support vector calls.

I have such a patch for GCC 15 but it's quite big and too invasive for stage-4.
As such this is a minimal fix, just don't apply the transformation and leave
targets which don't have the optab unoptimized.

Targets list for check_effective_target_ifn_copysign was gotten by grepping for
copysign and looking at the optab.

gcc/ChangeLog:

	PR tree-optimization/112468
	* doc/sourcebuild.texi: Document ifn_copysign.
	* match.pd: Only apply transformation if target supports the IFN.

gcc/testsuite/ChangeLog:

	PR tree-optimization/112468
	* gcc.dg/fold-copysign-1.c: Modify tests based on if target supports
	IFN_COPYSIGN.
	* gcc.dg/pr55152-2.c: Likewise.
	* gcc.dg/tree-ssa/abs-4.c: Likewise.
	* gcc.dg/tree-ssa/backprop-6.c: Likewise.
	* gcc.dg/tree-ssa/copy-sign-2.c: Likewise.
	* gcc.dg/tree-ssa/mult-abs-2.c: Likewise.
	* lib/target-supports.exp (check_effective_target_ifn_copysign): New.

diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index 3a394e7739b605677747fe33b9457b32ca14d030..2a96927e8bb5570558909a39554c6739008ce270 100644 (file)
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -2681,6 +2681,10 @@ Target requires a command line argument to enable a SIMD instruction set.
 @item xorsign
 Target supports the xorsign optab expansion.
 
+@item ifn_copysign
+Target supports the copysign optab expansion of float and double for
+both scalar and vector modes.
+
 @end table
 
 @subsubsection Environment attributes

diff --git a/gcc/match.pd b/gcc/match.pd
index 7b4b15acc412935ea86756720f6f6605a32b171f..d75babd86c259ca2dc6868bbfe4822c4edb88cbb 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1160,18 +1160,30 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
    (hypots @0 (copysigns @1 @2))
    (hypots @0 @1))))
 
-/* copysign(x, CST) -> abs (x).  */
+/* copysign(x, CST) -> abs (x).  If the target does not
+   support the copysign optab then canonicalize
+   copysign(x, -CST) -> fneg (abs (x)).   */
 (for copysigns (COPYSIGN_ALL)
  (simplify
   (copysigns @0 REAL_CST@1)
   (if (!REAL_VALUE_NEGATIVE (TREE_REAL_CST (@1)))
-   (abs @0))))
+   (abs @0)
+#if GIMPLE
+   (if (!direct_internal_fn_supported_p (IFN_COPYSIGN, type,
+                                        OPTIMIZE_FOR_BOTH))
+    (negate (abs @0)))
+#endif
+   )))
 
-/* Transform fneg (fabs (X)) -> copysign (X, -1).  */
+#if GIMPLE
+/* Transform fneg (fabs (X)) -> copysign (X, -1) as the canonical
+   representation if the target supports the copysign optab.  */
 (simplify
  (negate (abs @0))
- (IFN_COPYSIGN @0 { build_minus_one_cst (type); }))
-
+ (if (direct_internal_fn_supported_p (IFN_COPYSIGN, type,
+                                     OPTIMIZE_FOR_BOTH))
+   (IFN_COPYSIGN @0 { build_minus_one_cst (type); })))
+#endif
 /* copysign(copysign(x, y), z) -> copysign(x, z).  */
 (for copysigns (COPYSIGN_ALL)
  (simplify

diff --git a/gcc/testsuite/gcc.dg/fold-copysign-1.c b/gcc/testsuite/gcc.dg/fold-copysign-1.c
index f9cafd14ab05f5e8ab2f6f68e62801d21c2df6a6..96b80c733794fffada1b08274ef39cc8f6e442ce 100644 (file)
--- a/gcc/testsuite/gcc.dg/fold-copysign-1.c
+++ b/gcc/testsuite/gcc.dg/fold-copysign-1.c
@@ -1,5 +1,6 @@
 /* { dg-do compile } */
 /* { dg-options "-O -fdump-tree-cddce1" } */
+/* { dg-additional-options "-msse -mfpmath=sse" { target { { i?86-*-* x86_64-*-* } && ilp32 } } } */
 
 double foo (double x)
 {
@@ -12,5 +13,7 @@ double bar (double x)
   return __builtin_copysign (x, minuszero);
 }
 
-/* { dg-final { scan-tree-dump-times "__builtin_copysign" 1 "cddce1" } } */
-/* { dg-final { scan-tree-dump-times "= ABS_EXPR" 1 "cddce1" } } */
+/* { dg-final { scan-tree-dump-times "__builtin_copysign" 1 "cddce1" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times "= ABS_EXPR" 1 "cddce1" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times "= -" 1 "cddce1" { target { ! ifn_copysign } } } } */
+/* { dg-final { scan-tree-dump-times "= ABS_EXPR" 2 "cddce1" { target { ! ifn_copysign } } } } */

diff --git a/gcc/testsuite/gcc.dg/pr55152-2.c b/gcc/testsuite/gcc.dg/pr55152-2.c
index 605f202ed6bc7aa8fe921457b02ff0b88cc63ce6..24068cffa4a8e2807ba7d16c4ed3def4f736e797 100644 (file)
--- a/gcc/testsuite/gcc.dg/pr55152-2.c
+++ b/gcc/testsuite/gcc.dg/pr55152-2.c
@@ -1,5 +1,6 @@
 /* { dg-do compile } */
 /* { dg-options "-O -ffinite-math-only -fno-signed-zeros -fstrict-overflow -fdump-tree-optimized" } */
+/* { dg-additional-options "-msse -mfpmath=sse" { target { { i?86-*-* x86_64-*-* } && ilp32 } } } */
 
 double g (double a)
 {
@@ -10,5 +11,6 @@ int f(int a)
   return (a<-a)?a:-a;
 }
 
-/* { dg-final { scan-tree-dump-times "\.COPYSIGN" 1 "optimized" } } */
-/* { dg-final { scan-tree-dump-times "ABS_EXPR" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "\.COPYSIGN" 1 "optimized" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times "ABS_EXPR" 1 "optimized" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times "ABS_EXPR" 2 "optimized" { target { ! ifn_copysign } } } } */

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/abs-4.c b/gcc/testsuite/gcc.dg/tree-ssa/abs-4.c
index e1b825f37f69ac3c4666b3a52d733368805ad31d..80fa448df1259c7dba406797f4198205783a2fba 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/abs-4.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/abs-4.c
@@ -1,5 +1,6 @@
 /* { dg-do compile } */
 /* { dg-options "-O1 -fdump-tree-optimized" } */
+/* { dg-additional-options "-msse -mfpmath=sse" { target { { i?86-*-* x86_64-*-* } && ilp32 } } } */
 /* PR tree-optimization/109829 */
 
 float abs_f(float x) { return __builtin_signbit(x) ? x : -x; }
@@ -9,6 +10,8 @@ long double abs_ld(long double x) { return __builtin_signbit(x) ? x : -x; }
 
 /* __builtin_signbit(x) ? x : -x. Should be convert into - ABS_EXP<x> */
 /* { dg-final { scan-tree-dump-not "signbit" "optimized"} } */
-/* { dg-final { scan-tree-dump-times "= ABS_EXPR" 1 "optimized"} } */
-/* { dg-final { scan-tree-dump-times "= -" 1 "optimized"} } */
-/* { dg-final { scan-tree-dump-times "= \.COPYSIGN" 2 "optimized"} } */
+/* { dg-final { scan-tree-dump-times "= ABS_EXPR" 1 "optimized" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times "= -" 1 "optimized" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times "= \.COPYSIGN" 2 "optimized" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times "= ABS_EXPR" 3 "optimized" { target { ! ifn_copysign } } } } */
+/* { dg-final { scan-tree-dump-times "= -" 3 "optimized" { target { ! ifn_copysign } } } } */

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/backprop-6.c b/gcc/testsuite/gcc.dg/tree-ssa/backprop-6.c
index c3a138642d6ff7be984e91fa1343cb2718db7ae1..4087ba93018bb71710102eb379460bc760020081 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/backprop-6.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/backprop-6.c
@@ -1,5 +1,6 @@
 /* { dg-do compile } */
 /* { dg-options "-O -fdump-tree-backprop-details" }  */
+/* { dg-additional-options "-msse -mfpmath=sse" { target { { i?86-*-* x86_64-*-* } && ilp32 } } } */
 
 void start (void *);
 void end (void *);
@@ -26,6 +27,8 @@ TEST_FUNCTION (float, f)
 TEST_FUNCTION (double, )
 TEST_FUNCTION (long double, l)
 
-/* { dg-final { scan-tree-dump-times {Deleting[^\n]* = -} 4 "backprop" } } */
-/* { dg-final { scan-tree-dump-times {Deleting[^\n]* = \.COPYSIGN} 2 "backprop" } } */
-/* { dg-final { scan-tree-dump-times {Deleting[^\n]* = ABS_EXPR <} 1 "backprop" } } */
+/* { dg-final { scan-tree-dump-times {Deleting[^\n]* = -} 4 "backprop" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times {Deleting[^\n]* = \.COPYSIGN} 2 "backprop" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times {Deleting[^\n]* = ABS_EXPR <} 1 "backprop" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times {Deleting[^\n]* = -} 6 "backprop" { target { ! ifn_copysign } } } } */
+/* { dg-final { scan-tree-dump-times {Deleting[^\n]* = ABS_EXPR <} 3 "backprop" { target { ! ifn_copysign } } } } */

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/copy-sign-2.c b/gcc/testsuite/gcc.dg/tree-ssa/copy-sign-2.c
index e5d565c4b9832c00106588ef411fbd8c292a5cad..e43bc315bef2bd11c11cfd2685f5088e792b7bf7 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/copy-sign-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/copy-sign-2.c
@@ -1,4 +1,5 @@
 /* { dg-options "-O2 -ffast-math -fdump-tree-optimized" } */
+/* { dg-additional-options "-msse -mfpmath=sse" { target { { i?86-*-* x86_64-*-* } && ilp32 } } } */
 /* { dg-do compile } */
 float f(float x)
 {
@@ -10,5 +11,6 @@ float f1(float x)
   float t = __builtin_copysignf (1.0f, -x);
   return x * t;
 }
-/* { dg-final { scan-tree-dump-times "ABS" 1 "optimized"} } */
-/* { dg-final { scan-tree-dump-times ".COPYSIGN" 1 "optimized"} } */
+/* { dg-final { scan-tree-dump-times "ABS" 1 "optimized" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times ".COPYSIGN" 1 "optimized" { target ifn_copysign } } } */
+/* { dg-final { scan-tree-dump-times "ABS" 2 "optimized" { target { ! ifn_copysign } } } } */

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/mult-abs-2.c b/gcc/testsuite/gcc.dg/tree-ssa/mult-abs-2.c
index a22896b21c8b5a4d5d8e28bd8ae0db896e63ade0..675127cfe56b2e9aa9d4c06e2bdce62b59545a08 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/mult-abs-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/mult-abs-2.c
@@ -34,5 +34,5 @@ float i1(float x)
 {
   return x * (x <= 0.f ? 1.f : -1.f);
 }
-/* { dg-final { scan-tree-dump-times "ABS" 4 "gimple"} } */
-/* { dg-final { scan-tree-dump-times "\.COPYSIGN" 4 "gimple"} } */
+
+/* { dg-final { scan-tree-dump-times "ABS" 8 "gimple" } } */

diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index 4e329d207d771aebd90a808a62eae1bd722b3d24..43aa24a7c1d203f7d7ef516f654ba7e4cb158ec4 100644 (file)
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -7926,6 +7926,30 @@ proc check_effective_target_xorsign { } {
             || [istarget aarch64*-*-*] || [istarget arm*-*-*] }}]
 }
 
+# Return 1 if the target plus current options supports folding of
+# copysign into IFN_COPYSIGN.
+#
+# This won't change for different subtargets so cache the result.
+
+proc check_effective_target_ifn_copysign { } {
+    return [check_cached_effective_target_indexed ifn_copysign {
+      expr {
+        (([istarget i?86-*-*] || [istarget x86_64-*-*])
+          && [is-effective-target sse])
+        || ([istarget loongarch*-*-*]
+            && [check_effective_target_hard_float])
+        || ([istarget powerpc*-*-*]
+            && ![istarget powerpc-*-linux*paired*])
+        || [istarget alpha*-*-*]
+        || [istarget aarch64*-*-*]
+        || [is-effective-target arm_neon]
+        || ([istarget s390*-*-*]
+            && [check_effective_target_s390_vx])
+        || ([istarget riscv*-*-*]
+            && [check_effective_target_hard_float])
+       }}]
+}
+
 # Return 1 if the target plus current options supports a vector
 # widening summation of *short* args into *int* result, 0 otherwise.
 #