LoongArch: Standard instruction template fnmam4 correction

The current implementation of the fnmam4 instruction template requires
the third source operand to be assigned the same hard register as the
target operand, but the constraint is not documented in the instruction
manual or standard template definitions. The current constraint will
generate additional data dependencies and extra instructions.

gcc/ChangeLog:

	* config/loongarch/lasx.md (fnma<mode>4): Remove.
	* config/loongarch/lsx.md (fnma<mode>4): Remove.
	* config/loongarch/simd.md (fnma<mode>4): Simplify and correct.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/fnmam4-vec.c: New test.

(cherry picked from commit 7811fb6fa35fd3c3694eba34fbfc992eed1d3e67)

diff --git a/gcc/config/loongarch/lasx.md b/gcc/config/loongarch/lasx.md
index ae3997ddfaa88093af0b2a464d5a78d6bce9e732..974b83fc1e88c84e52a239301fe574a24e99eb56 100644 (file)
--- a/gcc/config/loongarch/lasx.md
+++ b/gcc/config/loongarch/lasx.md
@@ -1148,16 +1148,6 @@
   [(set_attr "type" "simd_fmadd")
    (set_attr "mode" "<MODE>")])
 
-(define_insn "fnma<mode>4"
-  [(set (match_operand:FLASX 0 "register_operand" "=f")
-       (fma:FLASX (neg:FLASX (match_operand:FLASX 1 "register_operand" "f"))
-                  (match_operand:FLASX 2 "register_operand" "f")
-                  (match_operand:FLASX 3 "register_operand" "0")))]
-  "ISA_HAS_LASX"
-  "xvfnmsub.<flasxfmt>\t%u0,%u1,%u2,%u0"
-  [(set_attr "type" "simd_fmadd")
-   (set_attr "mode" "<MODE>")])
-
 (define_expand "sqrt<mode>2"
   [(set (match_operand:FLASX 0 "register_operand")
     (sqrt:FLASX (match_operand:FLASX 1 "register_operand")))]

diff --git a/gcc/config/loongarch/lsx.md b/gcc/config/loongarch/lsx.md
index a674f2eb2cded35fd6b8fe4fdc30588c37c4f117..335d5b046d4f946acc7f0f244302d06c8f03a9ec 100644 (file)
--- a/gcc/config/loongarch/lsx.md
+++ b/gcc/config/loongarch/lsx.md
@@ -1006,16 +1006,6 @@
   [(set_attr "type" "simd_fmadd")
    (set_attr "mode" "<MODE>")])
 
-(define_insn "fnma<mode>4"
-  [(set (match_operand:FLSX 0 "register_operand" "=f")
-       (fma:FLSX (neg:FLSX (match_operand:FLSX 1 "register_operand" "f"))
-                 (match_operand:FLSX 2 "register_operand" "f")
-                 (match_operand:FLSX 3 "register_operand" "0")))]
-  "ISA_HAS_LSX"
-  "vfnmsub.<flsxfmt>\t%w0,%w1,%w2,%w0"
-  [(set_attr "type" "simd_fmadd")
-   (set_attr "mode" "<MODE>")])
-
 (define_expand "sqrt<mode>2"
   [(set (match_operand:FLSX 0 "register_operand")
     (sqrt:FLSX (match_operand:FLSX 1 "register_operand")))]

diff --git a/gcc/config/loongarch/simd.md b/gcc/config/loongarch/simd.md
index 691e719563626def42fbfa03bb24f54906ddf093..0e339dae382174d0267678fad01b3280b0b119bc 100644 (file)
--- a/gcc/config/loongarch/simd.md
+++ b/gcc/config/loongarch/simd.md
@@ -327,6 +327,17 @@
   [(set_attr "type" "simd_int_arith")
    (set_attr "mode" "<MODE>")])
 
+;; <x>vfnmsub.{s/d}
+(define_insn "fnma<mode>4"
+  [(set (match_operand:FVEC 0 "register_operand" "=f")
+       (fma:FVEC (neg:FVEC (match_operand:FVEC 1 "register_operand" "f"))
+                 (match_operand:FVEC 2 "register_operand" "f")
+                 (match_operand:FVEC 3 "register_operand" "f")))]
+  "!HONOR_SIGNED_ZEROS (<MODE>mode)"
+  "<x>vfnmsub.<simdfmt>\t%<wu>0,%<wu>1,%<wu>2,%<wu>3"
+  [(set_attr "type" "simd_fmadd")
+   (set_attr "mode" "<MODE>")])
+
 ;; <x>vfcmp.*.{s/d} with defined RTX code
 ;; There are no fcmp.{sugt/suge/cgt/cge}.{s/d} menmonics in GAS, so we have
 ;; to reverse the operands ourselves :(.

diff --git a/gcc/testsuite/gcc.target/loongarch/fnmam4-vec.c b/gcc/testsuite/gcc.target/loongarch/fnmam4-vec.c
new file mode 100644 (file)
index 0000000..0969303
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/fnmam4-vec.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -mlasx -ftree-vectorize" } */
+/* { dg-require-effective-target loongarch_asx } */
+
+void
+foo (float *u, float x, float *y, float z)
+{
+  int i;
+  for (i = 0; i < 1024; i++)
+    *(u++) = (x - y[i] * z);
+}
+
+/* { dg-final { scan-assembler-not "\tvori.b"} } */
+/* { dg-final { scan-assembler-not "\txvori.b"} } */