LRA, rs6000, Darwin: Revise lo_sum use for forced constants [PR104117].

Follow up discussion to the initial patch for this PR identified that it is
preferable to avoid the LRA change, and arrange for the target to reject the
hi and lo_sum selections when presented with an invalid address.

We split the Darwin high/low selectors into two:
 1. One that handles non-PIC addresses (kernel mode, mdynamic-no-pic).
 2. One that handles PIC addresses and rejects SYMBOL_REFs unless they are
    suitably wrapped in the MACHOPIC_OFFSET unspec.

The second case is handled by providing a new predicate (macho_pic_address)
that checks the requirements.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
	PR target/104117

gcc/ChangeLog:

	* config/rs6000/darwin.md (@machopic_high_<mode>): New.
	(@machopic_low_<mode>): New.
	* config/rs6000/predicates.md (macho_pic_address): New.
	* config/rs6000/rs6000.cc (rs6000_legitimize_address): Do not
	apply the TLS processing to Darwin.
	* lra-constraints.cc (process_address_1): Revert the changes
	in r12-7209.

diff --git a/gcc/config/rs6000/darwin.md b/gcc/config/rs6000/darwin.md
index 8443585df00dbe49dec8a2ff4bc4a6cc353b2514..e73d59e806688ceecfef3fe386fe456b338e0166 100644 (file)
--- a/gcc/config/rs6000/darwin.md
+++ b/gcc/config/rs6000/darwin.md
@@ -121,21 +121,32 @@ You should have received a copy of the GNU General Public License
    stw %0,lo16(%2)(%1)"
   [(set_attr "type" "store")])
 
-;; 64-bit MachO load/store support
-
 ;; Mach-O PIC.
 
 (define_insn "@macho_high_<mode>"
   [(set (match_operand:P 0 "gpc_reg_operand" "=b*r")
        (high:P (match_operand 1 "" "")))]
-  "TARGET_MACHO && (DEFAULT_ABI == ABI_DARWIN)"
+  "TARGET_MACHO && (DEFAULT_ABI == ABI_DARWIN) && !flag_pic"
   "lis %0,ha16(%1)")
 
 (define_insn "@macho_low_<mode>"
   [(set (match_operand:P 0 "gpc_reg_operand" "=r")
        (lo_sum:P (match_operand:P 1 "gpc_reg_operand" "b")
                   (match_operand 2 "" "")))]
-   "TARGET_MACHO && (DEFAULT_ABI == ABI_DARWIN)"
+   "TARGET_MACHO && (DEFAULT_ABI == ABI_DARWIN) && !flag_pic"
+   "la %0,lo16(%2)(%1)")
+
+(define_insn "@machopic_high_<mode>"
+  [(set (match_operand:P 0 "gpc_reg_operand" "=b*r")
+       (high:P (match_operand 1 "macho_pic_address" "")))]
+  "TARGET_MACHO && flag_pic"
+  "lis %0,ha16(%1)")
+
+(define_insn "@machopic_low_<mode>"
+  [(set (match_operand:P 0 "gpc_reg_operand" "=r")
+       (lo_sum:P (match_operand:P 1 "gpc_reg_operand" "b")
+                  (match_operand 2 "macho_pic_address" "")))]
+   "TARGET_MACHO && flag_pic"
    "la %0,lo16(%2)(%1)")
 
 (define_split

diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md
index c65dfb91f3dcbc1aaf813c3e789127fc3b28533e..28f6e9883cb74f99f6e121c6f0fb5f637a3b5146 100644 (file)
--- a/gcc/config/rs6000/predicates.md
+++ b/gcc/config/rs6000/predicates.md
@@ -2045,3 +2045,17 @@
  (if_then_else (match_test "TARGET_VSX")
   (match_operand 0 "reg_or_cint_operand")
   (match_operand 0 "const_int_operand")))
+
+;; Return true if the operand is a valid Mach-O pic address.
+;;
+(define_predicate "macho_pic_address"
+  (match_code "const,unspec")
+{
+  if (GET_CODE (op) == CONST)
+    op = XEXP (op, 0);
+
+  if (GET_CODE (op) == UNSPEC && XINT (op, 1) == UNSPEC_MACHOPIC_OFFSET)
+    return CONSTANT_P (XVECEXP (op, 0, 0));
+  else
+    return false;
+})

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 5b100a8f2fbecaab785775c0cd8adf279c8225d2..2388d44c8ccc520eb6be90f623e96600146501e3 100644 (file)
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -9021,7 +9021,7 @@ rs6000_legitimize_address (rtx x, rtx oldx ATTRIBUTE_UNUSED,
       else
        return force_reg (Pmode, x);
     }
-  if (SYMBOL_REF_P (x))
+  if (SYMBOL_REF_P (x) && !TARGET_MACHO)
     {
       enum tls_model model = SYMBOL_REF_TLS_MODEL (x);
       if (model != 0)

diff --git a/gcc/lra-constraints.cc b/gcc/lra-constraints.cc
index 5cd89e7eeddc279147c1bd145666b50da486a8ef..080b44ad87ab0fc2814829823be5148d0da873eb 100644 (file)
--- a/gcc/lra-constraints.cc
+++ b/gcc/lra-constraints.cc
@@ -3625,8 +3625,21 @@ process_address_1 (int nop, bool check_only_p,
                  *ad.inner = gen_rtx_LO_SUM (Pmode, new_reg, addr);
                  if (!valid_address_p (op, &ad, cn))
                    {
-                     *ad.inner = addr; /* Punt.  */
-                     code = -1;
+                     /* Try to put lo_sum into register.  */
+                     insn = emit_insn (gen_rtx_SET
+                                       (new_reg,
+                                        gen_rtx_LO_SUM (Pmode, new_reg, addr)));
+                     code = recog_memoized (insn);
+                     if (code >= 0)
+                       {
+                         *ad.inner = new_reg;
+                         if (!valid_address_p (op, &ad, cn))
+                           {
+                             *ad.inner = addr;
+                             code = -1;
+                           }
+                       }
+
                    }
                }
              if (code < 0)