[PATCH] x86-64: Use UNSPEC_DTPOFF to check source operand in TLS64_COMBINE

[H.J. Lu]

Since the first operand of PLUS in the source of TLS64_COMBINE pattern:

(set (reg/f:DI 128)
    (plus:DI (unspec:DI [
                (symbol_ref:DI ("_TLS_MODULE_BASE_") [flags 0x10])
                (reg:DI 126)
                (reg/f:DI 7 sp)
            ] UNSPEC_TLSDESC)
        (const:DI (unspec:DI [
                    (symbol_ref:DI ("bfd_error") [flags 0x1a] <var_decl 
0x7fffe99d6e40 bfd_error>)
                ] UNSPEC_DTPOFF))))

is unused, use the second operand of PLUS:

(const:DI (unspec:DI [
            (symbol_ref:DI ("bfd_error") [flags 0x1a] <var_decl 0x7fffe99d6e40 
bfd_error>)
        ] UNSPEC_DTPOFF))

to check if 2 TLS_COMBINE patterns have the same source.

gcc/

        PR target/121725
        * config/i386/i386-features.cc
        (pass_x86_cse::candidate_gnu2_tls_p): Use the UNSPEC_DTPOFF
        operand to check source operand in TLS64_COMBINE pattern.

gcc/testsuite/

        PR target/121725
        * gcc.target/i386/pr121725-1a.c: New test.
        * gcc.target/i386/pr121725-1b.c: Likewise.

Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
---
 gcc/config/i386/i386-features.cc            | 32 +++++-----------
 gcc/testsuite/gcc.target/i386/pr121725-1a.c | 41 +++++++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr121725-1b.c |  6 +++
 3 files changed, 57 insertions(+), 22 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr121725-1a.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr121725-1b.c

diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-features.cc
index 5440a02c442..0608dd2f9ac 100644
--- a/gcc/config/i386/i386-features.cc
+++ b/gcc/config/i386/i386-features.cc
@@ -4291,34 +4291,22 @@ pass_x86_cse::candidate_gnu2_tls_p (rtx set, attr_tls64 
tls64)
      */
 
       scalar_mode = mode = GET_MODE (src);
-      rtx src0 = XEXP (src, 0);
-      tls_symbol = XVECEXP (src0, 0, 0);
-      rtx src1 = XVECEXP (src0, 0, 1);
-      if (REG_P (src1))
-       {
-         set_insn = tls_set_insn_from_symbol (src1, tls_symbol);
-         gcc_assert (set_insn);
-       }
-      else
-       {
-         set_insn = nullptr;
-         gcc_assert (GET_CODE (src1) == UNSPEC
-                     && XINT (src1, 1) == UNSPEC_TLSDESC
-                     && SYMBOL_REF_P (XVECEXP (src1, 0, 0))
-                     && rtx_equal_p (XVECEXP (src1, 0, 0), tls_symbol));
-       }
 
-      /* Use TLS_SYMBOL and
+      /* Since the first operand of PLUS in the source TLS_COMBINE
+        pattern is unused, use the second operand of PLUS:
 
         (const:DI (unspec:DI [
                      (symbol_ref:DI ("e") [flags 0x1a])
                   ] UNSPEC_DTPOFF))
 
-        as VAL to check if 2 patterns have the same source.  */
-
-      rtvec vec = gen_rtvec (2, tls_symbol, XEXP (src, 1));
-      val = gen_rtx_UNSPEC (mode, vec, UNSPEC_TLSDESC);
-      def_insn = set_insn;
+        as VAL to check if 2 TLS_COMBINE patterns have the same
+        source.  */
+      val = XEXP (src, 1);
+      gcc_assert (GET_CODE (val) == CONST
+                 && GET_CODE (XEXP (val, 0)) == UNSPEC
+                     && XINT (XEXP (val, 0), 1) == UNSPEC_DTPOFF
+                     && SYMBOL_REF_P (XVECEXP (XEXP (val, 0), 0, 0)));
+      def_insn = nullptr;
       return true;
     }
 
diff --git a/gcc/testsuite/gcc.target/i386/pr121725-1a.c 
b/gcc/testsuite/gcc.target/i386/pr121725-1a.c
new file mode 100644
index 00000000000..d0a498cace9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr121725-1a.c
@@ -0,0 +1,41 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O3 -fpic -fplt -mtls-dialect=gnu" } */
+
+typedef enum
+{
+  bfd_error_invalid_error_code
+} bfd_error_type;
+static thread_local bfd_error_type bfd_error;
+extern int sections;
+extern void *bfd_alloc_ret;
+extern int bfd_alloc___o;
+extern long bfd_alloc_size;
+
+extern void _objalloc_alloc (int *, long);
+
+bfd_error_type
+bfd_get_error ()
+{
+  return bfd_error;
+}
+
+bool
+s7_bfd_score_elf_late_size_sections ()
+{
+  for (; sections;)
+    {
+      if (bfd_alloc_size)
+        {
+          bfd_error_type error_tag;
+          bfd_error = error_tag;
+        }
+      _objalloc_alloc (&bfd_alloc___o, 0);
+      if (bfd_alloc_ret)
+        {
+          bfd_error_type error_tag;
+          bfd_error = error_tag;
+        }
+    }
+}
+
+/* { dg-final { scan-assembler-times "call\[ \t\]__tls_get_addr@PLT" 2 { 
target { ! ia32 } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr121725-1b.c 
b/gcc/testsuite/gcc.target/i386/pr121725-1b.c
new file mode 100644
index 00000000000..0b97a8a4cb6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr121725-1b.c
@@ -0,0 +1,6 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O3 -fpic -fplt -mtls-dialect=gnu2" } */
+
+#include "pr121725-1a.c"
+
+/* { dg-final { scan-assembler-times "call\[ 
\t\]\\*bfd_error@TLSCALL\\(%(?:r|e)ax\\)" 2 { target { ! ia32 } } } } */
-- 
2.51.0