[RS6000] PR11848 rs6000_emit_move long double split

This split is disabled for power7 and up, so we don't often see its
bad effects.  However, on a powerpc-linux compiler (which defaults
to PPC750 judging from rs6000/sysv4.h) we see

	long double ld1 (void) { return 1.0L; }

compiled with -msoft-float -O2 -S resulting in

	ld1:
		li 3,0
		li 4,0
		mr 6,4
		mr 5,3
		li 4,0
		lis 3,0x3ff0
		blr

Things go awry in init-regs, with the TFmode reg being initialized to
zero on seeing the subreg from the split.  (And that initialization
itself is split by rs6000_emit_move!)  Later passes apparently don't
clean up the rubbish.

Since the split was added for Darwin (as the comment says), let's get
rid of it on other targets.

	* config/rs6000/rs6000.c (rs6000_emit_move): Disable long
	double split for targets other than Darwin.

From-SVN: r266610

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 011fe4c60ac02a0d36c3ff148d49b71b342c076b..36b1b2baa8b4318a9080d5b8d9d74b884e330ced 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2018-11-29  Alan Modra  <amodra@gmail.com>
+
+       * config/rs6000/rs6000.c (rs6000_emit_move): Disable long
+       double split for targets other than Darwin.
+
 2018-11-29  Alan Modra  <amodra@gmail.com>
 
        * config/rs6000/rs6000.md (movdi_internal64): Correct lengths.
@@ -692,7 +697,7 @@
 
 2018-11-23  Christoph Muellner  <christoph.muellner@theobroma-systems.com>
 
-        * config/aarch64/aarch64-cores.def: Define emag.
+       * config/aarch64/aarch64-cores.def: Define emag.
        * config/aarch64/aarch64-tune.md: Regenerated with emag.
        * config/aarch64/aarch64.c (emag_tunings): New struct.
        * doc/invoke.texi: Document mtune value.

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 93d58a2855fd2b1848df80a86557901b1393dbef..d986207a0c6528c119efa0ffe93a58d0cb2c73d7 100644 (file)
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -9967,8 +9967,8 @@ rs6000_emit_move (rtx dest, rtx source, machine_mode mode)
   /* 128-bit constant floating-point values on Darwin should really be loaded
      as two parts.  However, this premature splitting is a problem when DFmode
      values can go into Altivec registers.  */
-  if (FLOAT128_IBM_P (mode) && !reg_addr[DFmode].scalar_in_vmx_p
-      && GET_CODE (operands[1]) == CONST_DOUBLE)
+  if (TARGET_MACHO && CONST_DOUBLE_P (operands[1]) && FLOAT128_IBM_P (mode)
+      && !reg_addr[DFmode].scalar_in_vmx_p)
     {
       rs6000_emit_move (simplify_gen_subreg (DFmode, operands[0], mode, 0),
                        simplify_gen_subreg (DFmode, operands[1], mode, 0),