gcn: Fix __builtin_gcn_first_call_this_thread_p

Contrary naive expectation, unspec_volatile (via prologue_use) did not
prevent the cprop pass (at -O2) to remove the access to the s[0:1]
(PRIVATE_SEGMENT_BUFFER_ARG) register as the volatile got just put on
the preceeding pseudoregister.  Solution: Use gen_rtx_USE instead.
Additionally, this patch removes (gen_)prologue_use_di as it is then no
longer used.

Finally, as we already do bit manipulation, instead of using the full
64bit side - and then just keeping the value of 's0', just move directly
to use only s1 of s[0:1] and do the bit manipulations there, generating
more readable assembly code and better matching the '#else' branch.

gcc/ChangeLog:

	* config/gcn/gcn.cc (gcn_expand_builtin_1): Work on s1 instead
	of s[0:1] and use USE to prevent removal of setting that register.
	* config/gcn/gcn.md (prologue_use_di): Remove.

(cherry picked from commit 9fa67f1c1228a852e23943a41e68b664172c654c)

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index f8a49af76200855f555fa985cac2c4111740056b..48443438e395b65bffafd8fa9cd7026ced7ed62a 100644 (file)
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,3 +1,12 @@
+2022-11-28  Tobias Burnus  <tobias@codesourcery.com>
+
+       Backported from master:
+       2022-11-28  Tobias Burnus  <tobias@codesourcery.com>
+
+       * config/gcn/gcn.cc (gcn_expand_builtin_1): Work on s1 instead
+       of s[0:1] and use USE to prevent removal of setting that register.
+       * config/gcn/gcn.md (prologue_use_di): Remove.
+
 2022-11-26  Sandra Loosemore  <sandra@codesourcery.com>
 
        Backported from master:

diff --git a/gcc/config/gcn/gcn.cc b/gcc/config/gcn/gcn.cc
index 48a80ba103c1cfcf9f8014472d304a5fa5ffc3f0..85f20a46d67fc6abe529723aef3673e0ee89e16e 100644 (file)
--- a/gcc/config/gcn/gcn.cc
+++ b/gcc/config/gcn/gcn.cc
@@ -4589,8 +4589,9 @@ gcn_expand_builtin_1 (tree exp, rtx target, rtx /*subtarget */ ,
            rtx not_first = gen_label_rtx ();
            rtx reg = gen_rtx_REG (DImode,
                        cfun->machine->args.reg[PRIVATE_SEGMENT_BUFFER_ARG]);
-           rtx cmp = force_reg (DImode,
-                                gen_rtx_LSHIFTRT (DImode, reg, GEN_INT (48)));
+           reg = gcn_operand_part (DImode, reg, 1);
+           rtx cmp = force_reg (SImode,
+                                gen_rtx_LSHIFTRT (SImode, reg, GEN_INT (16)));
            emit_insn (gen_cstoresi4 (result, gen_rtx_NE (BImode, cmp,
                                                          GEN_INT(12345)),
                                      cmp, GEN_INT(12345)));
@@ -4598,12 +4599,11 @@ gcn_expand_builtin_1 (tree exp, rtx target, rtx /*subtarget */ ,
                                                              const0_rtx),
                                       result));
            emit_move_insn (reg,
-             force_reg (DImode,
-               gen_rtx_IOR (DImode,
-                            gen_rtx_AND (DImode, reg,
-                                         GEN_INT (0x0000ffffffffffffL)),
-                            GEN_INT (12345L << 48))));
-           emit_insn (gen_prologue_use (reg));
+             force_reg (SImode,
+               gen_rtx_IOR (SImode,
+                            gen_rtx_AND (SImode, reg, GEN_INT (0x0000ffff)),
+                            GEN_INT (12345L << 16))));
+           emit_insn (gen_rtx_USE (VOIDmode, reg));
            emit_label (not_first);
          }
        return result;

diff --git a/gcc/config/gcn/gcn.md b/gcc/config/gcn/gcn.md
index f31c20471daff2fc241d7d62f6fb0947b9c172ce..7e803f738bc996b99b18a7cf52fc925e0cfaa25a 100644 (file)
--- a/gcc/config/gcn/gcn.md
+++ b/gcc/config/gcn/gcn.md
@@ -726,19 +726,6 @@
   ""
   [(set_attr "length" "0")])
 
-(define_insn_and_split "prologue_use_di"
-  [(unspec_volatile [(match_operand:DI 0 "register_operand")] UNSPECV_PROLOGUE_USE)]
-  ""
-  "#"
-  "reload_completed"
-  [(unspec_volatile [(match_dup 0)] UNSPECV_PROLOGUE_USE)
-   (unspec_volatile [(match_dup 1)] UNSPECV_PROLOGUE_USE)]
-  {
-    operands[1] = gcn_operand_part (DImode, operands[0], 1);
-    operands[0] = gcn_operand_part (DImode, operands[0], 0);
-  }
-  [(set_attr "length" "0")])
-
 (define_expand "prologue"
   [(const_int 0)]
   ""