[PATCHv2, rs6000] Generate mfvsrwz for all subtargets and remove redundant zero extend [PR106769]

[HAO CHEN GUI <guihaoc@linux.ibm.com>]

Hi,
  This patch modifies vsx extract expand and generates mfvsrwz/stxsiwx
for all subtargets when the mode is V4SI and the index of extracted element
is 1 for BE and 2 for LE. Also this patch adds a insn pattern for mfvsrwz
which can help eliminate redundant zero extend.

  Compared to last version, the main change is to add a new expand for V4SI
and separate "vsx_extract_si" to 2 insn patterns.
https://gcc.gnu.org/pipermail/gcc-patches/2023-June/622101.html

  Bootstrapped and tested on powerpc64-linux BE and LE with no regressions.

Thanks
Gui Haochen


ChangeLog
rs6000: Generate mfvsrwz for all subtargets and remove redundant zero extend

mfvsrwz has lower latency than xxextractuw or vextuw[lr]x.  So it should be
generated even with p9 vector enabled.  Also the instruction is already
zero extended.  A combine pattern is needed to eliminate redundant zero
extend instructions.

gcc/
	PR target/106769
	* config/rs6000/vsx.md (expand vsx_extract_<mode>): Set it only
	for V8HI and V16QI.
	(vsx_extract_v4si): New expand for V4SI.
	(*vsx_extract_<mode>_di_p9): Not generate the insn when it can
	be generated by mfvsrwz.
	(mfvsrwz): New insn pattern for zero extended vsx_extract_v4si.
	(*vsx_extract_si): Removed.
	(vsx_extract_v4si_0): New insn pattern to deal with V4SI extract
	when the index of extracted element is 1 with BE and 2 with LE.
	(vsx_extract_v4si_1): New insn and split pattern which deals with
	the cases not handled by vsx_extract_v4si_0.

gcc/testsuite/
	PR target/106769
	* gcc.target/powerpc/pr106769.h: New.
	* gcc.target/powerpc/pr106769-p8.c: New.
	* gcc.target/powerpc/pr106769-p9.c: New.

patch.diff
diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
index 0a34ceebeb5..ad249441bcf 100644
--- a/gcc/config/rs6000/vsx.md
+++ b/gcc/config/rs6000/vsx.md
@@ -3722,9 +3722,9 @@ (define_insn "vsx_xxpermdi2_<mode>_1"
 (define_expand  "vsx_extract_<mode>"
   [(parallel [(set (match_operand:<VEC_base> 0 "gpc_reg_operand")
 		   (vec_select:<VEC_base>
-		    (match_operand:VSX_EXTRACT_I 1 "gpc_reg_operand")
+		    (match_operand:VSX_EXTRACT_I2 1 "gpc_reg_operand")
 		    (parallel [(match_operand:QI 2 "const_int_operand")])))
-	      (clobber (match_scratch:VSX_EXTRACT_I 3))])]
+	      (clobber (match_scratch:VSX_EXTRACT_I2 3))])]
   "VECTOR_MEM_VSX_P (<MODE>mode) && TARGET_DIRECT_MOVE_64BIT"
 {
   /* If we have ISA 3.0, we can do a xxextractuw/vextractu{b,h}.  */
@@ -3736,6 +3736,23 @@ (define_expand  "vsx_extract_<mode>"
     }
 })

+(define_expand  "vsx_extract_v4si"
+  [(parallel [(set (match_operand:SI 0 "gpc_reg_operand")
+		   (vec_select:SI
+		    (match_operand:V4SI 1 "gpc_reg_operand")
+		    (parallel [(match_operand:QI 2 "const_0_to_3_operand")])))
+	      (clobber (match_scratch:V4SI 3))])]
+  "TARGET_DIRECT_MOVE_64BIT"
+{
+  if (TARGET_P9_VECTOR
+      && INTVAL (operands[2]) != (BYTES_BIG_ENDIAN ? 1 : 2))
+    {
+      emit_insn (gen_vsx_extract_v4si_p9 (operands[0], operands[1],
+					  operands[2]));
+      DONE;
+    }
+})
+
 (define_insn "vsx_extract_<mode>_p9"
   [(set (match_operand:<VEC_base> 0 "gpc_reg_operand" "=r,<VSX_EX>")
 	(vec_select:<VEC_base>
@@ -3798,7 +3815,9 @@ (define_insn_and_split "*vsx_extract_<mode>_di_p9"
 	  (match_operand:VSX_EXTRACT_I 1 "gpc_reg_operand" "v,<VSX_EX>")
 	  (parallel [(match_operand:QI 2 "const_int_operand" "n,n")]))))
    (clobber (match_scratch:SI 3 "=r,X"))]
-  "VECTOR_MEM_VSX_P (<MODE>mode) && TARGET_VEXTRACTUB"
+  "TARGET_VEXTRACTUB
+   && (<MODE>mode != V4SImode
+       || INTVAL (operands[2]) != (BYTES_BIG_ENDIAN ? 1 : 2))"
   "#"
   "&& reload_completed"
   [(parallel [(set (match_dup 4)
@@ -3830,58 +3849,78 @@ (define_insn_and_split "*vsx_extract_<mode>_store_p9"
    (set (match_dup 0)
 	(match_dup 3))])

-(define_insn_and_split  "*vsx_extract_si"
+(define_insn "mfvsrwz"
+  [(set (match_operand:DI 0 "register_operand" "=r")
+	(zero_extend:DI
+	  (vec_select:SI
+	    (match_operand:V4SI 1 "vsx_register_operand" "wa")
+	    (parallel [(match_operand:QI 2 "const_int_operand" "n")]))))
+   (clobber (match_scratch:V4SI 3 "=v"))]
+  "TARGET_DIRECT_MOVE_64BIT
+   && INTVAL (operands[2]) == (BYTES_BIG_ENDIAN ? 1 : 2)"
+  "mfvsrwz %0,%x1"
+  [(set_attr "type" "mfvsr")
+   (set_attr "isa" "p8v")])
+
+(define_insn "vsx_extract_v4si_0"
+  [(set (match_operand:SI 0 "nonimmediate_operand" "=r,wa,Z,wa")
+	(vec_select:SI
+	 (match_operand:V4SI 1 "gpc_reg_operand" "v,v,v,0")
+	 (parallel [(match_operand:QI 2 "const_0_to_3_operand" "n,n,n,n")])))
+   (clobber (match_scratch:V4SI 3 "=v,v,v,v"))]
+  "TARGET_DIRECT_MOVE_64BIT
+   && (!TARGET_P9_VECTOR || INTVAL (operands[2]) == (BYTES_BIG_ENDIAN ? 1 : 2))"
+{
+   if (which_alternative == 0)
+     return "mfvsrwz %0,%x1";
+
+   if (which_alternative == 1)
+     return "xxlor %x0,%x1,%x1";
+
+   if (which_alternative == 2)
+     return "stxsiwx %x1,%y0";
+
+   return ASM_COMMENT_START " vec_extract to same register";
+}
+  [(set_attr "type" "mfvsr,veclogical,fpstore,*")
+   (set_attr "length" "4,4,4,0")
+   (set_attr "isa" "p8v,*,p8v,*")])
+
+(define_insn_and_split "vsx_extract_v4si_1"
   [(set (match_operand:SI 0 "nonimmediate_operand" "=r,wa,Z")
 	(vec_select:SI
 	 (match_operand:V4SI 1 "gpc_reg_operand" "v,v,v")
 	 (parallel [(match_operand:QI 2 "const_0_to_3_operand" "n,n,n")])))
    (clobber (match_scratch:V4SI 3 "=v,v,v"))]
-  "VECTOR_MEM_VSX_P (V4SImode) && TARGET_DIRECT_MOVE_64BIT && !TARGET_P9_VECTOR"
+  "TARGET_DIRECT_MOVE_64BIT
+   && !TARGET_P9_VECTOR
+   && INTVAL (operands[2]) != (BYTES_BIG_ENDIAN ? 1 : 2)"
   "#"
-  "&& reload_completed"
+  "&& 1"
   [(const_int 0)]
 {
   rtx dest = operands[0];
   rtx src = operands[1];
   rtx element = operands[2];
-  rtx vec_tmp = operands[3];
-  int value;
+  rtx vec_tmp;
+
+  if (GET_CODE (operands[3]) == SCRATCH)
+    vec_tmp = gen_reg_rtx (V4SImode);
+  else
+    vec_tmp = operands[3];

   /* Adjust index for LE element ordering, the below minuend 3 is computed by
      GET_MODE_NUNITS (V4SImode) - 1.  */
   if (!BYTES_BIG_ENDIAN)
     element = GEN_INT (3 - INTVAL (element));

-  /* If the value is in the correct position, we can avoid doing the VSPLT<x>
-     instruction.  */
-  value = INTVAL (element);
-  if (value != 1)
-    emit_insn (gen_altivec_vspltw_direct (vec_tmp, src, element));
-  else
-    vec_tmp = src;
+  emit_insn (gen_altivec_vspltw_direct (vec_tmp, src, element));

-  if (MEM_P (operands[0]))
-    {
-      if (can_create_pseudo_p ())
-	dest = rs6000_force_indexed_or_indirect_mem (dest);
-
-      if (TARGET_P8_VECTOR)
-	emit_move_insn (dest, gen_rtx_REG (SImode, REGNO (vec_tmp)));
-      else
-	emit_insn (gen_stfiwx (dest, gen_rtx_REG (DImode, REGNO (vec_tmp))));
-    }
-
-  else if (TARGET_P8_VECTOR)
-    emit_move_insn (dest, gen_rtx_REG (SImode, REGNO (vec_tmp)));
-  else
-    emit_move_insn (gen_rtx_REG (DImode, REGNO (dest)),
-		    gen_rtx_REG (DImode, REGNO (vec_tmp)));
+  int value = BYTES_BIG_ENDIAN ? 1 : 2;
+  emit_insn (gen_vsx_extract_v4si_0 (dest, vec_tmp, GEN_INT (value)));

   DONE;
-}
-  [(set_attr "type" "mfvsr,vecperm,fpstore")
-   (set_attr "length" "8")
-   (set_attr "isa" "*,p8v,*")])
+})

 (define_insn_and_split  "*vsx_extract_<mode>_p8"
   [(set (match_operand:<VEC_base> 0 "nonimmediate_operand" "=r")
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106769-p8.c b/gcc/testsuite/gcc.target/powerpc/pr106769-p8.c
new file mode 100644
index 00000000000..e7cdbc76298
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106769-p8.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-skip-if "" { powerpc*-*-darwin* } } */
+/* { dg-require-effective-target powerpc_p8vector_ok } */
+/* { dg-options "-mdejagnu-cpu=power8 -O2" } */
+/* { dg-require-effective-target has_arch_ppc64 } */
+
+#include "pr106769.h"
+
+/* { dg-final { scan-assembler {\mmfvsrwz\M} } } */
+/* { dg-final { scan-assembler {\mstxsiwx\M} } } */
+/* { dg-final { scan-assembler-not {\mrldicl\M} } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106769-p9.c b/gcc/testsuite/gcc.target/powerpc/pr106769-p9.c
new file mode 100644
index 00000000000..2205e434a86
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106769-p9.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-skip-if "" { powerpc*-*-darwin* } } */
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-options "-mdejagnu-cpu=power9 -O2" } */
+/* { dg-require-effective-target has_arch_ppc64 } */
+
+#include "pr106769.h"
+
+/* { dg-final { scan-assembler {\mmfvsrwz\M} } } */
+/* { dg-final { scan-assembler {\mstxsiwx\M} } } */
+/* { dg-final { scan-assembler-not {\mrldicl\M} } } */
+/* { dg-final { scan-assembler-not {\mxxextractuw\M} } } */
+/* { dg-final { scan-assembler-not "vextuw\[rl\]x" } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106769.h b/gcc/testsuite/gcc.target/powerpc/pr106769.h
new file mode 100644
index 00000000000..1c8c8a024f3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106769.h
@@ -0,0 +1,17 @@
+#include <altivec.h>
+
+#ifdef __BIG_ENDIAN__
+#define LANE 1
+#else
+#define LANE 2
+#endif
+
+unsigned int foo1 (vector unsigned int v)
+{
+   return vec_extract(v, LANE);
+}
+
+void foo2 (vector unsigned int v, unsigned int* p)
+{
+   *p = vec_extract(v, LANE);
+}