rs6000: Consider inline asm as safe if no assembler complains [PR111828]

As discussed in PR111828, rs6000_update_ipa_fn_target_info
is much conservative, currently for any non-empty inline
asm, without any parsing, it would take inline asm could
have HTM insns.  It means for one function attributed with
power8 having inline asm, even if it has no HTM insns, we
don't make a function attributed with power10 inline it.

Peter pointed out an inline asm parser can be a slippery
slope, and noticed that the current gnu assembler still
allows HTM insns even with power10 machine type, so he
suggested that we can aggressively ignore the handling on
inline asm, this patch goes for this suggestion.

Considering that there are a few assembler alternatives
and assembler can update its behaviors (complaining HTM
insns at power10 and later cpus sounds reasonable from a
certain point of view), this patch also checks assembler
complains on HTM insns at power10 or not.  For a case that
a caller attributed power10 calls a callee attributed
power8 having inline asm with HTM insn, without inlining
at least the compilation succeeds, but if assembler
complains HTM insns at power10, after inlining the
compilation would fail.

The two associated test cases are fine without and with
this patch (effective target takes effect or not).

	PR target/111828

gcc/ChangeLog:

	* config.in: Regenerate.
	* config/rs6000/rs6000.cc (rs6000_update_ipa_fn_target_info): Guard
	inline asm handling under !HAVE_AS_POWER10_HTM.
	* configure: Regenerate.
	* configure.ac: Detect assembler support for HTM insns at power10.

gcc/testsuite/ChangeLog:

	* lib/target-supports.exp
	(check_effective_target_powerpc_as_p10_htm): New proc.
	* g++.target/powerpc/pr111828-1.C: New test.
	* g++.target/powerpc/pr111828-2.C: New test.

(cherry picked from commit b2075291af8810794c7184fd125b991c2341cb1e)

diff --git a/gcc/config.in b/gcc/config.in
index 4cad077bfbed7fd73b3c04ce6405fd2f49178412..ef35af16f2f1d7d8ee9e6dbf5bbfb664e6e0f4ab 100644 (file)
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -678,6 +678,12 @@
 #endif
 
 
+/* Define if your assembler supports htm insns on power10. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_AS_POWER10_HTM
+#endif
+
+
 /* Define if your assembler supports .ref */
 #ifndef USED_FOR_TARGET
 #undef HAVE_AS_REF

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 063bb0242bfac3b23e2e002aca5cd1c3967e01cb..e5ceff3a61b755f39078329568697f8fd8fe5ace 100644 (file)
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -25412,6 +25412,7 @@ rs6000_need_ipa_fn_target_info (const_tree decl,
 static bool
 rs6000_update_ipa_fn_target_info (unsigned int &info, const gimple *stmt)
 {
+#ifndef HAVE_AS_POWER10_HTM
   /* Assume inline asm can use any instruction features.  */
   if (gimple_code (stmt) == GIMPLE_ASM)
     {
@@ -25423,7 +25424,9 @@ rs6000_update_ipa_fn_target_info (unsigned int &info, const gimple *stmt)
        info |= RS6000_FN_TARGET_INFO_HTM;
       return false;
     }
-  else if (gimple_code (stmt) == GIMPLE_CALL)
+#endif
+
+  if (gimple_code (stmt) == GIMPLE_CALL)
     {
       tree fndecl = gimple_call_fndecl (stmt);
       if (fndecl && fndecl_built_in_p (fndecl, BUILT_IN_MD))

diff --git a/gcc/configure b/gcc/configure
index c7b26d1927de62d7b3a49ea9ac0a998979659cf2..0ab71aa3bcdce0c2852c45c12f5de4339e3c2efc 100755 (executable)
--- a/gcc/configure
+++ b/gcc/configure
@@ -28077,6 +28077,49 @@ if test $gcc_cv_as_powerpc_mfcrf = yes; then
 
 $as_echo "#define HAVE_AS_MFCRF 1" >>confdefs.h
 
+fi
+
+
+    case $target in
+      *-*-aix*) conftest_s='   .machine "pwr10"
+       .csect .text[PR]
+       tend. 0';;
+      *-*-darwin*) conftest_s='        .text
+       tend. 0';;
+      *) conftest_s='  .machine power10
+       .text
+       tend. 0';;
+    esac
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for htm support on Power10" >&5
+$as_echo_n "checking assembler for htm support on Power10... " >&6; }
+if ${gcc_cv_as_power10_htm+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  gcc_cv_as_power10_htm=no
+  if test x$gcc_cv_as != x; then
+    $as_echo "$conftest_s" > conftest.s
+    if { ac_try='$gcc_cv_as $gcc_cv_as_flags  -o conftest.o conftest.s >&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+    then
+       gcc_cv_as_power10_htm=yes
+    else
+      echo "configure: failed program was" >&5
+      cat conftest.s >&5
+    fi
+    rm -f conftest.o conftest.s
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_power10_htm" >&5
+$as_echo "$gcc_cv_as_power10_htm" >&6; }
+if test $gcc_cv_as_power10_htm = yes; then
+
+$as_echo "#define HAVE_AS_POWER10_HTM 1" >>confdefs.h
+
 fi
 
 

diff --git a/gcc/configure.ac b/gcc/configure.ac
index 09082e8ccae395b902a3ef79eb4f27a1186a331e..fcd45f54c7d9fdd15a76ab487e9df78755c51b92 100644 (file)
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5032,6 +5032,23 @@ gd:
       [AC_DEFINE(HAVE_AS_MFCRF, 1,
          [Define if your assembler supports mfcr field.])])
 
+    case $target in
+      *-*-aix*) conftest_s='   .machine "pwr10"
+       .csect .text[[PR]]
+       tend. 0';;
+      *-*-darwin*) conftest_s='        .text
+       tend. 0';;
+      *) conftest_s='  .machine power10
+       .text
+       tend. 0';;
+    esac
+
+    gcc_GAS_CHECK_FEATURE([htm support on Power10],
+      gcc_cv_as_power10_htm,,
+      [$conftest_s],,
+      [AC_DEFINE(HAVE_AS_POWER10_HTM, 1,
+         [Define if your assembler supports htm insns on power10.])])
+
     case $target in
       *-*-aix*) conftest_s='   .csect .text[[PR]]
 LCF..0:

diff --git a/gcc/testsuite/g++.target/powerpc/pr111828-1.C b/gcc/testsuite/g++.target/powerpc/pr111828-1.C
new file mode 100644 (file)
index 0000000..d76a084
--- /dev/null
+++ b/gcc/testsuite/g++.target/powerpc/pr111828-1.C
@@ -0,0 +1,49 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_as_p10_htm } */
+/* Use -Wno-attributes to suppress the possible warning on always_inline.  */
+/* { dg-options "-O2 -mdejagnu-cpu=power9 -Wno-attributes" } */
+
+/* Verify it doesn't emit any error messages.  */
+
+#include <stddef.h>
+#define HWY_PRAGMA(tokens) _Pragma (#tokens)
+#define HWY_PUSH_ATTRIBUTES(targets_str) HWY_PRAGMA (GCC target targets_str)
+__attribute__ ((always_inline)) void
+PreventElision (int output)
+{
+  asm("nop" : "+r"(output) : : "memory");
+}
+#define HWY_BEFORE_NAMESPACE() HWY_PUSH_ATTRIBUTES (",cpu=power10")
+HWY_BEFORE_NAMESPACE () namespace detail
+{
+  template <typename, size_t, int> struct CappedTagChecker
+  {
+  };
+}
+template <typename T, size_t kLimit, int kPow2 = 0>
+using CappedTag = detail::CappedTagChecker<T, kLimit, kPow2>;
+template <typename, size_t, size_t kMinArg, class Test> struct ForeachCappedR
+{
+  static void Do (size_t, size_t)
+  {
+    CappedTag<int, kMinArg> d;
+    Test () (int(), d);
+  }
+};
+template <class Test> struct ForPartialVectors
+{
+  template <typename T> void operator() (T)
+  {
+    ForeachCappedR<T, 1, 1, Test>::Do (1, 1);
+  }
+};
+struct TestFloorLog2
+{
+  template <class T, class DF> void operator() (T, DF) { PreventElision (0x10); }
+};
+void
+TestAllFloorLog2 ()
+{
+  ForPartialVectors<TestFloorLog2> () (float());
+}
+

diff --git a/gcc/testsuite/g++.target/powerpc/pr111828-2.C b/gcc/testsuite/g++.target/powerpc/pr111828-2.C
new file mode 100644 (file)
index 0000000..0b73316
--- /dev/null
+++ b/gcc/testsuite/g++.target/powerpc/pr111828-2.C
@@ -0,0 +1,52 @@
+/* { dg-do compile } */
+/* { dg-skip-if "HTM inline asm supported" { powerpc_as_p10_htm } } */
+/* Use -Wno-attributes to suppress the possible warning on always_inline.  */
+/* { dg-options "-O2 -mdejagnu-cpu=power9 -Wno-attributes" } */
+
+/* Verify it emits error messages on non-empty inline asm.  */
+
+#include <stddef.h>
+#define HWY_PRAGMA(tokens) _Pragma (#tokens)
+#define HWY_PUSH_ATTRIBUTES(targets_str) HWY_PRAGMA (GCC target targets_str)
+__attribute__ ((always_inline)) void
+PreventElision (int output) /* { dg-error "inlining failed in call to .* target specific option mismatch" } */
+{
+  asm("nop" : "+r"(output) : : "memory");
+}
+#define HWY_BEFORE_NAMESPACE() HWY_PUSH_ATTRIBUTES (",cpu=power10")
+HWY_BEFORE_NAMESPACE () namespace detail
+{
+  template <typename, size_t, int> struct CappedTagChecker
+  {
+  };
+}
+template <typename T, size_t kLimit, int kPow2 = 0>
+using CappedTag = detail::CappedTagChecker<T, kLimit, kPow2>;
+template <typename, size_t, size_t kMinArg, class Test> struct ForeachCappedR
+{
+  static void Do (size_t, size_t)
+  {
+    CappedTag<int, kMinArg> d;
+    Test () (int(), d);
+  }
+};
+template <class Test> struct ForPartialVectors
+{
+  template <typename T> void operator() (T)
+  {
+    ForeachCappedR<T, 1, 1, Test>::Do (1, 1);
+  }
+};
+struct TestFloorLog2
+{
+  template <class T, class DF> void operator() (T, DF)
+  {
+    PreventElision (0x10); /* { dg-message "called from here" } */
+  }
+};
+void
+TestAllFloorLog2 ()
+{
+  ForPartialVectors<TestFloorLog2> () (float());
+}
+

diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index 40f71e9ed8b951f695ad02b02de7a7b8b08e2969..4d6bf2eb8d32d562d61962e2fed5d448760fefa7 100644 (file)
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -12263,6 +12263,46 @@ proc check_effective_target_o_flag_in_section { } {
     }]
 }
 
+# Return 1 if the given assembler supports hardware transactional memory
+# instructions with machine type Power10, 0 otherwise.  Cache the result.
+
+proc check_effective_target_powerpc_as_p10_htm { } {
+    global tool
+    global GCC_UNDER_TEST
+
+    # Need auto-host.h to check linker support.
+    if { ![file exists ../../auto-host.h ] } {
+       return 0
+    }
+
+    return [check_cached_effective_target powerpc_as_p10_htm {
+
+       set src pie[pid].c
+       set obj pie[pid].o
+
+       set f [open $src "w"]
+       puts $f "#include \"../../auto-host.h\""
+       puts $f "#if HAVE_AS_POWER10_HTM == 0"
+       puts $f "# error Assembler does not support htm insns with power10."
+       puts $f "#endif"
+       close $f
+
+       verbose "check_effective_target_powerpc_as_p10_htm compiling testfile $src" 2
+       set lines [${tool}_target_compile $src $obj object ""]
+
+       file delete $src
+       file delete $obj
+
+       if [string match "" $lines] then {
+           verbose "check_effective_target_powerpc_as_p10_htm testfile compilation passed" 2
+           return 1
+       } else {
+           verbose "check_effective_target_powerpc_as_p10_htm testfile compilation failed" 2
+           return 0
+       }
+    }]
+}
+
 # return 1 if LRA is supported.
 
 proc check_effective_target_lra { } {