[PATCH, powerpc] PR 53199, fix usage of __builtin_bswap64 on power6

Michael Meissner meissner@linux.vnet.ibm.com
Thu May 3 17:57:00 GMT 2012


In trying to build machine specific versions of glibc with newer compilers, we
ran into a bug where the current glibc would not build on power6.  This was due
to glibc using the __builtin_swap64 builtin.  Power6 sets the
-mavoid-indexed-addresses option.  The splitter that I wrote when I wrote the
bswap64 did not have an alternate code path for -mavoid-indexed-addresses.
This patch adds the alternate code path.  I bootstraped it with today's
compiler and there were no regressions in make check.  Is it ok to apply?

[gcc]
2012-05-03  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/53199
	* config/rs6000/rs6000.md (bswapdi splitters): If
	-mavoid-indexed-addresses (or -mcpu=power6 which sets it by
	default) is used, generate an alternate sequence that does not
	depend on using indexed addressing.

[gcc/testsuite]
2012-05-03  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/53199
	* gcc.target/powwerpc/pr53199.c: New file.


-- 
Michael Meissner, IBM
5 Technology Place Drive, M/S 2757, Westford, MA 01886-3141, USA
meissner@linux.vnet.ibm.com	fax +1 (978) 399-6899
-------------- next part --------------
Index: gcc/config/rs6000/rs6000.md
===================================================================
--- gcc/config/rs6000/rs6000.md	(revision 187099)
+++ gcc/config/rs6000/rs6000.md	(working copy)
@@ -2550,7 +2550,18 @@ (define_split
   if (GET_CODE (addr1) == PLUS)
     {
       emit_insn (gen_add3_insn (op2, XEXP (addr1, 0), GEN_INT (4)));
-      addr2 = gen_rtx_PLUS (Pmode, op2, XEXP (addr1, 1));
+      if (TARGET_AVOID_XFORM)
+	{
+	  emit_insn (gen_add3_insn (op2, XEXP (addr1, 1), op2));
+	  addr2 = op2;
+	}
+      else
+	addr2 = gen_rtx_PLUS (Pmode, op2, XEXP (addr1, 1));
+    }
+  else if (TARGET_AVOID_XFORM)
+    {
+      emit_insn (gen_add3_insn (op2, addr1, GEN_INT (4)));
+      addr2 = op2;
     }
   else
     {
@@ -2600,7 +2611,18 @@ (define_split
   if (GET_CODE (addr1) == PLUS)
     {
       emit_insn (gen_add3_insn (op2, XEXP (addr1, 0), GEN_INT (4)));
-      addr2 = gen_rtx_PLUS (Pmode, op2, XEXP (addr1, 1));
+      if (TARGET_AVOID_XFORM)
+	{
+	  emit_insn (gen_add3_insn (op2, XEXP (addr1, 1), op2));
+	  addr2 = op2;
+	}
+      else
+	addr2 = gen_rtx_PLUS (Pmode, op2, XEXP (addr1, 1));
+    }
+  else if (TARGET_AVOID_XFORM)
+    {
+      emit_insn (gen_add3_insn (op2, addr1, GEN_INT (4)));
+      addr2 = op2;
     }
   else
     {
@@ -2681,7 +2703,18 @@ (define_split
   if (GET_CODE (addr1) == PLUS)
     {
       emit_insn (gen_add3_insn (op2, XEXP (addr1, 0), GEN_INT (4)));
-      addr2 = gen_rtx_PLUS (SImode, op2, XEXP (addr1, 1));
+      if (TARGET_AVOID_XFORM)
+	{
+	  emit_insn (gen_add3_insn (op2, XEXP (addr1, 1), op2));
+	  addr2 = op2;
+	}
+      else
+	addr2 = gen_rtx_PLUS (SImode, op2, XEXP (addr1, 1));
+    }
+  else if (TARGET_AVOID_XFORM)
+    {
+      emit_insn (gen_add3_insn (op2, addr1, GEN_INT (4)));
+      addr2 = op2;
     }
   else
     {
@@ -2726,7 +2759,18 @@ (define_split
   if (GET_CODE (addr1) == PLUS)
     {
       emit_insn (gen_add3_insn (op2, XEXP (addr1, 0), GEN_INT (4)));
-      addr2 = gen_rtx_PLUS (SImode, op2, XEXP (addr1, 1));
+      if (TARGET_AVOID_XFORM)
+	{
+	  emit_insn (gen_add3_insn (op2, XEXP (addr1, 1), op2));
+	  addr2 = op2;
+	}
+      else
+	addr2 = gen_rtx_PLUS (SImode, op2, XEXP (addr1, 1));
+    }
+  else if (TARGET_AVOID_XFORM)
+    {
+      emit_insn (gen_add3_insn (op2, addr1, GEN_INT (4)));
+      addr2 = op2;
     }
   else
     {
Index: gcc/testsuite/gcc.target/powerpc/pr53199.c
===================================================================
--- gcc/testsuite/gcc.target/powerpc/pr53199.c	(revision 0)
+++ gcc/testsuite/gcc.target/powerpc/pr53199.c	(revision 0)
@@ -0,0 +1,50 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-skip-if "" { powerpc*-*-darwin* } { "*" } { "" } } */
+/* { dg-options "-O2 -mcpu=power6 -mavoid-indexed-addresses" } */
+/* { dg-final { scan-assembler-times "lwbrx" 6 } } */
+/* { dg-final { scan-assembler-times "stwbrx" 6 } } */
+
+/* PR 51399: bswap gets an error if -mavoid-indexed-addresses was used in
+   creating the two lwbrx instructions.  */
+
+long long
+load64_reverse_1 (long long *p)
+{
+  return __builtin_bswap64 (*p);
+}
+
+long long
+load64_reverse_2 (long long *p)
+{
+  return __builtin_bswap64 (p[1]);
+}
+
+long long
+load64_reverse_3 (long long *p, int i)
+{
+  return __builtin_bswap64 (p[i]);
+}
+
+void
+store64_reverse_1 (long long *p, long long x)
+{
+  *p = __builtin_bswap64 (x);
+}
+
+void
+store64_reverse_2 (long long *p, long long x)
+{
+  p[1] = __builtin_bswap64 (x);
+}
+
+void
+store64_reverse_3 (long long *p, long long x, int i)
+{
+  p[i] = __builtin_bswap64 (x);
+}
+
+long long
+reg_reverse (long long x)
+{
+  return __builtin_bswap64 (x);
+}


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