[PATCH V2] rs6000: Support to build constants by li/lis+oris/xoris

Jiufu Guo guojiufu@linux.ibm.com
Wed Oct 26 11:40:52 GMT 2022


Hi,

PR106708 constaint some constants which can be support by li/lis + oris/xoris.

For constant C:
if '(c & 0xFFFFFFFF80008000ULL) == 0x80000000ULL' or say:
32(0) || 1(1) || 15(x) || 1(0) || 15(x), we could use li+oris to
build constant 'C'.
Here N(M) means N continuous bit M, x for M means it is ok for either
1 or 0; '||' means concatenation.

if '(c & 0xFFFFFFFF00008000ULL) == 0xFFFFFFFF00008000ULL' or say:
32(1) || 16(x) || 1(1) || 15(x), using li+xoris would be ok.

if '(c & 0xFFFFFFFF0000FFFFULL) == 0xFFFFFFFF00000000' or say:
32(1) || 1(0) || 15(x) || 16(0), using lis+xoris would be ok.

This patch update rs6000_emit_set_long_const to support these forms.
Bootstrap and regtest pass on ppc64 and ppc64le.

Is this ok for trunk?

BR,
Jeff(Jiufu)


	PR target/106708

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Support
	constants which can be built with li + oris or li/lis + xoris.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr106708-run.c: New test.
	* gcc.target/powerpc/pr106708.c: New test.
	* gcc.target/powerpc/pr106708.h: New file.

---
 gcc/config/rs6000/rs6000.cc                   | 41 ++++++++++++++-----
 .../gcc.target/powerpc/pr106708-run.c         | 17 ++++++++
 gcc/testsuite/gcc.target/powerpc/pr106708.c   | 12 ++++++
 gcc/testsuite/gcc.target/powerpc/pr106708.h   |  9 ++++
 4 files changed, 69 insertions(+), 10 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708-run.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.h

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index d2743f7bce6..9b7a51f052d 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -10228,6 +10228,7 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
 {
   rtx temp;
   HOST_WIDE_INT ud1, ud2, ud3, ud4;
+  HOST_WIDE_INT orig_c = c;
 
   ud1 = c & 0xffff;
   c = c >> 16;
@@ -10253,21 +10254,41 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
 			gen_rtx_IOR (DImode, copy_rtx (temp),
 				     GEN_INT (ud1)));
     }
+  else if ((ud4 == 0xffff && ud3 == 0xffff)
+	   && ((ud1 & 0x8000) || (ud1 == 0 && !(ud2 & 0x8000))))
+    {
+      temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
+
+      HOST_WIDE_INT imm = (ud1 & 0x8000) ? ((ud1 ^ 0x8000) - 0x8000)
+					 : ((ud2 << 16) - 0x80000000);
+      /* li/lis + xoris */
+      emit_move_insn (temp, GEN_INT (imm));
+      emit_move_insn (dest, gen_rtx_XOR (DImode, temp,
+					 GEN_INT (orig_c ^ imm)));
+    }
   else if (ud3 == 0 && ud4 == 0)
     {
       temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
 
       gcc_assert (ud2 & 0x8000);
-      emit_move_insn (copy_rtx (temp),
-		      GEN_INT (((ud2 << 16) ^ 0x80000000) - 0x80000000));
-      if (ud1 != 0)
-	emit_move_insn (copy_rtx (temp),
-			gen_rtx_IOR (DImode, copy_rtx (temp),
-				     GEN_INT (ud1)));
-      emit_move_insn (dest,
-		      gen_rtx_ZERO_EXTEND (DImode,
-					   gen_lowpart (SImode,
-							copy_rtx (temp))));
+
+      if (!(ud1 & 0x8000))
+	{
+	  /* li+oris */
+	  emit_move_insn (temp, GEN_INT (ud1));
+	  emit_move_insn (dest,
+			  gen_rtx_IOR (DImode, temp, GEN_INT (ud2 << 16)));
+	}
+      else
+	{
+	  emit_move_insn (temp,
+			  GEN_INT (((ud2 << 16) ^ 0x80000000) - 0x80000000));
+	  if (ud1 != 0)
+	    emit_move_insn (temp, gen_rtx_IOR (DImode, temp, GEN_INT (ud1)));
+	  emit_move_insn (dest,
+			  gen_rtx_ZERO_EXTEND (DImode,
+					       gen_lowpart (SImode, temp)));
+	}
     }
   else if (ud1 == ud3 && ud2 == ud4)
     {
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708-run.c b/gcc/testsuite/gcc.target/powerpc/pr106708-run.c
new file mode 100644
index 00000000000..df65c321f6b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106708-run.c
@@ -0,0 +1,17 @@
+/* PR target/106708 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "pr106708.h"
+
+long long arr[] = {0x98765432ULL, 0xffffffff7cdeab55ULL, 0xffffffff65430000ULL};
+int
+main ()
+{
+  long long a[3];
+
+  foo (a);
+  if (__builtin_memcmp (a, arr, sizeof (arr)) != 0)
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.c b/gcc/testsuite/gcc.target/powerpc/pr106708.c
new file mode 100644
index 00000000000..ebd9ea88993
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106708.c
@@ -0,0 +1,12 @@
+/* PR target/106708 */
+/* { dg-do compile } } */
+/* { dg-options "-O2 -mdejagnu-cpu=power8" } */
+/* { dg-require-effective-target has_arch_ppc64 } */
+
+
+#include "pr106708.h"
+
+/* { dg-final { scan-assembler-times {\mli\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mlis\M} 1 } } */
+/* { dg-final { scan-assembler-times {\moris\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxoris\M} 2 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.h b/gcc/testsuite/gcc.target/powerpc/pr106708.h
new file mode 100644
index 00000000000..42526a70892
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106708.h
@@ -0,0 +1,9 @@
+/* Test constants which can be built by li/lis + oris/xoris */
+void  __attribute__ ((__noinline__, __noclone__)) foo (long long *arg)
+{
+  *arg++ = 0x98765432ULL;
+  *arg++ = 0xffffffff7cdeab55ULL;
+  *arg++ = 0xffffffff65430000ULL;
+}
+
+
-- 
2.17.1



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