Patchwork [powerpc] , PR 57744, fix quad word atomic instructions to use even/odd registers

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Submitter Michael Meissner
Date June 28, 2013, 4:19 p.m.
Message ID <20130628161923.GA5166@ibm-tiger.the-meissners.org>
Download mbox | patch
Permalink /patch/255463/
State New
Headers show

Comments

Michael Meissner - June 28, 2013, 4:19 p.m.
On Fri, Jun 28, 2013 at 11:39:46AM -0400, David Edelsohn wrote:
> Only the PTI change is okay.

As we discussed over IRC, this is the patch that I committed.

[gcc]
2013-06-28  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/57744
	* config/rs6000/rs6000.h (MODES_TIEABLE_P): Do not allow PTImode
	to tie with any other modes.  Eliminate Altivec vector mode tests,
	since these are a subset of ALTIVEC or VSX vector modes.  Simplify
	code, to return 0 if testing MODE2 for a condition, if we've
	already tested MODE1 for the same condition.

[gcc/testsuite]
2013-06-28  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/57744
	* gcc.target/powerpc/pr57744.c: New test to make sure lqarx and
	stqcx. get even registers.

Patch

Index: gcc/config/rs6000/rs6000.h
===================================================================
--- gcc/config/rs6000/rs6000.h	(revision 200535)
+++ gcc/config/rs6000/rs6000.h	(working copy)
@@ -1180,28 +1180,32 @@  enum data_align { align_abi, align_opt, 
 /* Value is 1 if it is a good idea to tie two pseudo registers
    when one has mode MODE1 and one has mode MODE2.
    If HARD_REGNO_MODE_OK could produce different values for MODE1 and MODE2,
-   for any hard reg, then this must be 0 for correct output.  */
+   for any hard reg, then this must be 0 for correct output.
+
+   PTImode cannot tie with other modes because PTImode is restricted to even
+   GPR registers, and TImode can go in any GPR as well as VSX registers (PR
+   57744).  */
 #define MODES_TIEABLE_P(MODE1, MODE2)		\
-  (SCALAR_FLOAT_MODE_P (MODE1)			\
+  ((MODE1) == PTImode				\
+   ? (MODE2) == PTImode				\
+   : (MODE2) == PTImode				\
+   ? 0						\
+   : SCALAR_FLOAT_MODE_P (MODE1)		\
    ? SCALAR_FLOAT_MODE_P (MODE2)		\
    : SCALAR_FLOAT_MODE_P (MODE2)		\
-   ? SCALAR_FLOAT_MODE_P (MODE1)		\
+   ? 0						\
    : GET_MODE_CLASS (MODE1) == MODE_CC		\
    ? GET_MODE_CLASS (MODE2) == MODE_CC		\
    : GET_MODE_CLASS (MODE2) == MODE_CC		\
-   ? GET_MODE_CLASS (MODE1) == MODE_CC		\
+   ? 0						\
    : SPE_VECTOR_MODE (MODE1)			\
    ? SPE_VECTOR_MODE (MODE2)			\
    : SPE_VECTOR_MODE (MODE2)			\
-   ? SPE_VECTOR_MODE (MODE1)			\
+   ? 0						\
    : ALTIVEC_OR_VSX_VECTOR_MODE (MODE1)		\
    ? ALTIVEC_OR_VSX_VECTOR_MODE (MODE2)		\
    : ALTIVEC_OR_VSX_VECTOR_MODE (MODE2)		\
-   ? ALTIVEC_OR_VSX_VECTOR_MODE (MODE1)		\
-   : ALTIVEC_VECTOR_MODE (MODE1)		\
-   ? ALTIVEC_VECTOR_MODE (MODE2)		\
-   : ALTIVEC_VECTOR_MODE (MODE2)		\
-   ? ALTIVEC_VECTOR_MODE (MODE1)		\
+   ? 0						\
    : 1)
 
 /* Post-reload, we can't use any new AltiVec registers, as we already
Index: gcc/testsuite/gcc.target/powerpc/pr57744.c
===================================================================
--- gcc/testsuite/gcc.target/powerpc/pr57744.c	(revision 0)
+++ gcc/testsuite/gcc.target/powerpc/pr57744.c	(revision 0)
@@ -0,0 +1,37 @@ 
+/* { dg-do run { target { powerpc*-*-* && lp64 } } } */
+/* { dg-skip-if "" { powerpc*-*-darwin* } { "*" } { "" } } */
+/* { dg-require-effective-target powerpc_p8vector_ok } */
+/* { dg-options "-mcpu=power8 -O3" } */
+
+typedef unsigned U_16 __attribute__((mode(TI)));
+
+extern int libat_compare_exchange_16 (U_16 *, U_16 *, U_16, int, int)
+  __attribute__((__noinline__));
+
+/* PR 57744: lqarx/stqcx needs even/odd register pairs.  The assembler will
+   complain if the compiler gets an odd/even register pair.  Create a function
+   which has the 16 byte compare and exchange instructions, but don't actually
+   execute it, so that we can detect these failures on older machines. */
+
+int
+libat_compare_exchange_16 (U_16 *mptr, U_16 *eptr, U_16 newval,
+         int smodel, int fmodel __attribute__((unused)))
+{
+  if (((smodel) == 0))
+    return __atomic_compare_exchange_n (mptr, eptr, newval, 0, 0, 0);
+  else if (((smodel) != 5))
+    return __atomic_compare_exchange_n (mptr, eptr, newval, 0, 4, 0);
+  else
+    return __atomic_compare_exchange_n (mptr, eptr, newval, 0, 5, 0);
+}
+
+U_16 a = 1, b = 1, c = -2;
+volatile int do_test = 0;
+
+int main (void)
+{
+  if (do_test && !libat_compare_exchange_16 (&a, &b, c, 0, 0))
+    aborrt ();
+
+  return 0;
+}