[PowerPC] Allow -mfloat128 option for VSX targets

Targets with VSX feature but without native float128 instructions can
also use that type with supplementary libcalls. We don't enable it by
default now because Glibc assumes long double and float128 can be
implicitly converted in between, which is not available under default
'ibmlongdouble' semantics in clang.

This commit partly relands cbd93ce.

diff --git a/clang/lib/Basic/Targets/PPC.cpp b/clang/lib/Basic/Targets/PPC.cpp
index 7f7b44b..19b7ded 100644 (file)
--- a/clang/lib/Basic/Targets/PPC.cpp
+++ b/clang/lib/Basic/Targets/PPC.cpp
@@ -561,9 +561,9 @@ bool PPCTargetInfo::initFeatureMap(
   if (!ppcUserFeaturesCheck(Diags, FeaturesVec))
     return false;
 
-  if (!(ArchDefs & ArchDefinePwr9) && (ArchDefs & ArchDefinePpcgr) &&
+  if (!(ArchDefs & ArchDefinePwr7) && (ArchDefs & ArchDefinePpcgr) &&
       llvm::is_contained(FeaturesVec, "+float128")) {
-    // We have __float128 on PPC but not power 9 and above.
+    // We have __float128 on PPC but not pre-VSX targets.
     Diags.Report(diag::err_opt_not_valid_with_opt) << "-mfloat128" << CPU;
     return false;
   }

diff --git a/clang/test/Driver/ppc-f128-support-check.c b/clang/test/Driver/ppc-f128-support-check.c
index 2474890..616d641 100644 (file)
--- a/clang/test/Driver/ppc-f128-support-check.c
+++ b/clang/test/Driver/ppc-f128-support-check.c
@@ -2,13 +2,17 @@
 // RUN:   -mcpu=pwr9 -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=HASF128
 // RUN: not %clang -target powerpc64le-unknown-linux-gnu -fsyntax-only \
 // RUN:   -mcpu=power9 -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=HASF128
-
 // RUN: not %clang -target powerpc64le-unknown-linux-gnu -fsyntax-only \
-// RUN:   -mcpu=pwr8 -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=NOF128
+// RUN:   -mcpu=pwr8 -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=HASF128
+// RUN: not %clang -target powerpc64le-unknown-linux-gnu -fsyntax-only \
+// RUN:   -mcpu=pwr7 -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=HASF128
+// RUN: not %clang -target powerpc64le-unknown-linux-gnu -fsyntax-only \
+// RUN:   -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=HASF128
+
 // RUN: not %clang -target powerpc64le-unknown-linux-gnu -fsyntax-only \
-// RUN:   -mcpu=pwr7 -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=NOF128
+// RUN:   -mcpu=pwr6 -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=NOF128
 // RUN: not %clang -target powerpc64le-unknown-linux-gnu -fsyntax-only \
-// RUN:   -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=NOF128
+// RUN:   -mno-vsx -mfloat128 %s 2>&1 | FileCheck %s --check-prefix=NOF128
 
 #ifdef __FLOAT128__
 static_assert(false, "__float128 enabled");