[PATCH] gcc/configure.ac: fix register issue for global_load assembler functions

Marcel Vollweiler marcel@codesourcery.com
Thu Jun 17 13:50:49 GMT 2021


Am 16.06.2021 um 19:19 schrieb Joseph Myers:
> On Wed, 16 Jun 2021, Julian Brown wrote:
>
>>> +    if test x$gcc_cv_as_gcn_global_load_fixed = xyes; then
>>> +      AC_DEFINE(HAVE_GCN_ASM_GLOBAL_LOAD_FIXED, 1, [Define if your
>>> assembler has fixed global_load functions.])
>>> +    else
>>> +      AC_DEFINE(HAVE_GCN_ASM_GLOBAL_LOAD_FIXED, 0, [Define if your
>>> assembler has fixed global_load functions.])
>>> +    fi
>>> +    AC_MSG_RESULT($gcc_cv_as_gcn_global_load_fixed)
>>> +    ;;
>>> +esac
>>
>> I think the more-common idiom seems to be just having a single
>> AC_DEFINE if the feature is present -- like (as a random example)
>> HAVE_AS_IX86_REP_LOCK_PREFIX, which omits the "define ... 0" case you
>> have here. (You'd use "#ifdef ..." instead of "#if ... == 1" to check
>> the feature then, of course).
>
> Actually I think what's preferable is the approach used with e.g.
> GATHER_STATISTICS - define to 0 or 1 using a single AC_DEFINE_UNQUOTED
> call (via a shell variable that's set to 0 or 1 as appropriate), then test
> in "if" conditions, not #if, as far as possible, so that both alternatives
> in the conditional code always get syntax-checked when compiling GCC (for
> this target).
>

Thank you for your proposals. I adapted configure.ac and gcn.c
accordingly (similar to the GATHER_STATISTICS example).

Marcel
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-------------- next part --------------
gcc/configure.ac: Adapt configuration according to assembler fix of global_load functions.

gcc/ChangeLog:

	* config.in: Regenerate.
	* config/gcn/gcn.c (print_operand_address): Fix for global_load assembler
	functions.
	* configure: Regenerate.
	* configure.ac: Fix for global_load assembler functions. 

diff --git a/gcc/config.in b/gcc/config.in
index e54f59c..18e6271 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -1431,6 +1431,12 @@
 #endif
 
 
+/* Define if your assembler has fixed global_load functions. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_GCN_ASM_GLOBAL_LOAD_FIXED
+#endif
+
+
 /* Define to 1 if you have the `getchar_unlocked' function. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_GETCHAR_UNLOCKED
diff --git a/gcc/config/gcn/gcn.c b/gcc/config/gcn/gcn.c
index 283a91f..54a1c0b 100644
--- a/gcc/config/gcn/gcn.c
+++ b/gcc/config/gcn/gcn.c
@@ -5481,13 +5481,22 @@ print_operand_address (FILE *file, rtx mem)
 	      if (vgpr_offset == NULL_RTX)
 		/* In this case, the vector offset is zero, so we use the first
 		   lane of v1, which is initialized to zero.  */
-		fprintf (file, "v[1:2]");
+		{
+		  if (HAVE_GCN_ASM_GLOBAL_LOAD_FIXED)
+		    fprintf (file, "v1");
+		  else
+		    fprintf (file, "v[1:2]");
+		}
 	      else if (REG_P (vgpr_offset)
 		       && VGPR_REGNO_P (REGNO (vgpr_offset)))
 		{
-		  fprintf (file, "v[%d:%d]",
-			   REGNO (vgpr_offset) - FIRST_VGPR_REG,
-			   REGNO (vgpr_offset) - FIRST_VGPR_REG + 1);
+		  if (HAVE_GCN_ASM_GLOBAL_LOAD_FIXED)
+		    fprintf (file, "v%d",
+			     REGNO (vgpr_offset) - FIRST_VGPR_REG);
+		  else
+		    fprintf (file, "v[%d:%d]",
+			     REGNO (vgpr_offset) - FIRST_VGPR_REG,
+			     REGNO (vgpr_offset) - FIRST_VGPR_REG + 1);
 		}
 	      else
 		output_operand_lossage ("bad ADDR_SPACE_GLOBAL address");
diff --git a/gcc/configure b/gcc/configure
index 4a9e4fa..dd0194a 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -28909,6 +28909,33 @@ case "$target" in
     ;;
 esac
 
+# This tests if the assembler supports two registers for global_load functions
+# (like in LLVM versions <12) or one register (like in LLVM 12).
+case "$target" in
+  amdgcn-* | gcn-*)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler fix for global_load functions" >&5
+$as_echo_n "checking assembler fix for global_load functions... " >&6; }
+    gcc_cv_as_gcn_global_load_fixed=yes
+    if test x$gcc_cv_as != x; then
+      cat > conftest.s <<EOF
+	global_store_dwordx2    v[1:2], v[4:5], s[14:15]
+EOF
+      if $gcc_cv_as -triple=amdgcn--amdhsa -filetype=obj -mcpu=gfx900 -o conftest.o conftest.s > /dev/null 2>&1; then
+        gcc_cv_as_gcn_global_load_fixed=no
+      fi
+      rm -f conftest.s conftest.o conftest
+    fi
+    global_load_fixed=`if test x$gcc_cv_as_gcn_global_load_fixed = xyes; then echo 1; else echo 0; fi`
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_GCN_ASM_GLOBAL_LOAD_FIXED $global_load_fixed
+_ACEOF
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_gcn_global_load_fixed" >&5
+$as_echo "$gcc_cv_as_gcn_global_load_fixed" >&6; }
+    ;;
+esac
+
 # ??? Not all targets support dwarf2 debug_line, even within a version
 # of gas.  Moreover, we need to emit a valid instruction to trigger any
 # info to the output file.  So, as supported targets are added to gas 2.11,
diff --git a/gcc/configure.ac b/gcc/configure.ac
index d9fc3c2..5f30f80 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5357,6 +5357,28 @@ case "$target" in
     ;;
 esac
 
+# This tests if the assembler supports two registers for global_load functions
+# (like in LLVM versions <12) or one register (like in LLVM 12).
+case "$target" in
+  amdgcn-* | gcn-*)
+    AC_MSG_CHECKING(assembler fix for global_load functions)
+    gcc_cv_as_gcn_global_load_fixed=yes
+    if test x$gcc_cv_as != x; then
+      cat > conftest.s <<EOF
+	global_store_dwordx2    v[[1:2]], v[[4:5]], s[[14:15]]
+EOF
+      if $gcc_cv_as -triple=amdgcn--amdhsa -filetype=obj -mcpu=gfx900 -o conftest.o conftest.s > /dev/null 2>&1; then
+        gcc_cv_as_gcn_global_load_fixed=no
+      fi
+      rm -f conftest.s conftest.o conftest
+    fi
+    global_load_fixed=`if test x$gcc_cv_as_gcn_global_load_fixed = xyes; then echo 1; else echo 0; fi`
+    AC_DEFINE_UNQUOTED(HAVE_GCN_ASM_GLOBAL_LOAD_FIXED, $global_load_fixed,
+      [Define if your assembler has fixed global_load functions.])
+    AC_MSG_RESULT($gcc_cv_as_gcn_global_load_fixed)
+    ;;
+esac
+
 # ??? Not all targets support dwarf2 debug_line, even within a version
 # of gas.  Moreover, we need to emit a valid instruction to trigger any
 # info to the output file.  So, as supported targets are added to gas 2.11,


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