PATCH: PR target/66232: -fPIC -fno-plt -mx32 fails to generate indirect branch via GOT

From 118cf4c2c928608f7ad7edd0812d6f2f880dbd55 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 17 Dec 2015 08:42:06 -0800
Subject: [PATCH] Allow indirect call via GOT for 64-bit Pmode x32

Since Pmode is 64-bit with -maddress-mode=long for x32, indirect call
via GOT slot doesn't need zero_extend.  This patch enables indirect call
via GOT for x32 with 64-bit Pmode.

gcc/

	PR target/66232
	* config/i386/constraints.md (Bs): Allow GOT slot for x32 with
	64-bit Pmode.
	(Bw): Likewise.
	(Bz): Likewise.
	* config/i386/predicates.md (call_insn_operand): Likewise.
	(sibcall_insn_operand): Likewise.

gcc/testsuite/

	PR target/66232
	* gcc.target/i386/pr66232-10.c: New test.
	* gcc.target/i386/pr66232-11.c: Likewise.
	* gcc.target/i386/pr66232-12.c: Likewise.
	* gcc.target/i386/pr66232-13.c: Likewise.
---
 gcc/config/i386/constraints.md             | 12 +++++++----
 gcc/config/i386/predicates.md              | 32 +++++++++++++++++-------------
 gcc/testsuite/gcc.target/i386/pr66232-10.c | 13 ++++++++++++
 gcc/testsuite/gcc.target/i386/pr66232-11.c | 14 +++++++++++++
 gcc/testsuite/gcc.target/i386/pr66232-12.c | 13 ++++++++++++
 gcc/testsuite/gcc.target/i386/pr66232-13.c | 13 ++++++++++++
 6 files changed, 79 insertions(+), 18 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr66232-10.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr66232-11.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr66232-12.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr66232-13.c

diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md
index 2861d8d..b46d32b 100644
--- a/gcc/config/i386/constraints.md
+++ b/gcc/config/i386/constraints.md
@@ -162,13 +162,17 @@ 
 
 (define_constraint "Bs"
   "@internal Sibcall memory operand."
-  (and (not (match_test "TARGET_X32"))
-       (match_operand 0 "sibcall_memory_operand")))
+  (ior (and (not (match_test "TARGET_X32"))
+	    (match_operand 0 "sibcall_memory_operand"))
+       (and (match_test "TARGET_X32 && Pmode == DImode")
+	    (match_operand 0 "GOT_memory_operand"))))
 
 (define_constraint "Bw"
   "@internal Call memory operand."
-  (and (not (match_test "TARGET_X32"))
-       (match_operand 0 "memory_operand")))
+  (ior (and (not (match_test "TARGET_X32"))
+	    (match_operand 0 "memory_operand"))
+       (and (match_test "TARGET_X32 && Pmode == DImode")
+	    (match_operand 0 "GOT_memory_operand"))))
 
 (define_constraint "Bz"
   "@internal Constant call address operand."
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
index 8bdd5d8..ab8ef06 100644
--- a/gcc/config/i386/predicates.md
+++ b/gcc/config/i386/predicates.md
@@ -606,32 +606,36 @@ 
 			&& GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
 			&& XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
 
+;; Return true if OP is a GOT memory operand.
+(define_predicate "GOT_memory_operand"
+  (match_operand 0 "memory_operand")
+{
+  op = XEXP (op, 0);
+  return (GET_CODE (op) == CONST
+	  && GET_CODE (XEXP (op, 0)) == UNSPEC
+	  && XINT (XEXP (op, 0), 1) == UNSPEC_GOTPCREL);
+})
+
 ;; Test for a valid operand for a call instruction.
 ;; Allow constant call address operands in Pmode only.
 (define_special_predicate "call_insn_operand"
   (ior (match_test "constant_call_address_operand
 		     (op, mode == VOIDmode ? mode : Pmode)")
        (match_operand 0 "call_register_no_elim_operand")
-       (and (not (match_test "TARGET_X32"))
-	    (match_operand 0 "memory_operand"))))
+       (ior (and (not (match_test "TARGET_X32"))
+		 (match_operand 0 "sibcall_memory_operand"))
+	    (and (match_test "TARGET_X32 && Pmode == DImode")
+		 (match_operand 0 "GOT_memory_operand")))))
 
 ;; Similarly, but for tail calls, in which we cannot allow memory references.
 (define_special_predicate "sibcall_insn_operand"
   (ior (match_test "constant_call_address_operand
 		     (op, mode == VOIDmode ? mode : Pmode)")
        (match_operand 0 "register_no_elim_operand")
-       (and (not (match_test "TARGET_X32"))
-	    (match_operand 0 "sibcall_memory_operand"))))
-
-;; Return true if OP is a GOT memory operand.
-(define_predicate "GOT_memory_operand"
-  (match_operand 0 "memory_operand")
-{
-  op = XEXP (op, 0);
-  return (GET_CODE (op) == CONST
-	  && GET_CODE (XEXP (op, 0)) == UNSPEC
-	  && XINT (XEXP (op, 0), 1) == UNSPEC_GOTPCREL);
-})
+       (ior (and (not (match_test "TARGET_X32"))
+		 (match_operand 0 "sibcall_memory_operand"))
+	    (and (match_test "TARGET_X32 && Pmode == DImode")
+		 (match_operand 0 "GOT_memory_operand")))))
 
 ;; Match exactly zero.
 (define_predicate "const0_operand"
diff --git a/gcc/testsuite/gcc.target/i386/pr66232-10.c b/gcc/testsuite/gcc.target/i386/pr66232-10.c
new file mode 100644
index 0000000..c4e9157
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66232-10.c
@@ -0,0 +1,13 @@ 
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-require-effective-target maybe_x32 } */
+/* { dg-options "-O2 -mx32 -fpic -fno-plt -maddress-mode=long" } */
+
+extern void bar (void);
+
+void
+foo (void)
+{
+  bar ();
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOTPCREL" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr66232-11.c b/gcc/testsuite/gcc.target/i386/pr66232-11.c
new file mode 100644
index 0000000..05794af
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66232-11.c
@@ -0,0 +1,14 @@ 
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-require-effective-target maybe_x32 } */
+/* { dg-options "-O2 -mx32 -fpic -fno-plt -maddress-mode=long" } */
+
+extern void bar (void);
+
+int
+foo (void)
+{
+  bar ();
+  return 0;
+}
+
+/* { dg-final { scan-assembler "call\[ \t\]*.bar@GOTPCREL" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr66232-12.c b/gcc/testsuite/gcc.target/i386/pr66232-12.c
new file mode 100644
index 0000000..313b9e4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66232-12.c
@@ -0,0 +1,13 @@ 
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-require-effective-target maybe_x32 } */
+/* { dg-options "-O2 -mx32 -fpic -fno-plt -maddress-mode=long" } */
+
+extern int bar (void);
+
+int
+foo (void)
+{
+  return bar ();
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOTPCREL" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr66232-13.c b/gcc/testsuite/gcc.target/i386/pr66232-13.c
new file mode 100644
index 0000000..50a12cf
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66232-13.c
@@ -0,0 +1,13 @@ 
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-require-effective-target maybe_x32 } */
+/* { dg-options "-O2 -mx32 -fpic -fno-plt -maddress-mode=long" } */
+
+extern int bar (void);
+
+int
+foo (void)
+{
+  return bar () + 1;
+}
+
+/* { dg-final { scan-assembler "call\[ \t\]*.bar@GOTPCREL" } } */
-- 
2.5.0