[clang][Arm] Fix handling of -Wa,-march=

[DavidSpickett]

Summary

This fixes Bugzilla #48894 for Arm, where it
was reported that -Wa,-march was not being handled
by the integrated assembler.

This was previously fixed for -Wa,-mthumb by
parsing the argument in ToolChain::ComputeLLVMTriple
instead of CollectArgsForIntegratedAssembler.
It has to be done in the former because the Triple
is read only by the time we get to the latter.

Previously only mcpu would work via -Wa but only because
"-target-cpu" is it's own option to cc1, which we were
able to modify. Target architecture is part of "-target-triple".

This change applies the same workaround to -march and cleans up
handling of -Wa,-mcpu at the same time. There were some
places where we were not using the last instance of an argument.

The existing -Wa,-mthumb code was doing this correctly,
so I've just added tests to confirm that.

Now the same rules will apply to -Wa,-march/-mcpu as would
if you just passed them to the compiler:

• -Wa/-Xassembler options only apply to assembly files.
• Architecture derived from mcpu beats any march options.
• When there are multiple mcpu or multiple march, the last one wins.
• If there is a compiler option and an assembler option of the same type, we prefer the one that fits the input type.
• If there is an applicable mcpu option but it is overruled by an march, the cpu value is still used for the "-target-cpu" cc1 option.

[DavidSpickett]

Bug link: https://bugs.llvm.org/show_bug.cgi?id=48894

[DavidSpickett]

clang/lib/Driver/ToolChain.cpp

753

Suffix originally set here, from any compiler options.

807

Then we override that if we're using the assembler and have -Wa options.

[nickdesaulniers]

Wow, thank you so much for the work that went into this patch! Very thorough tests. Just minor questions about yet more test cases. Patch LGTM.

clang/test/Driver/arm-target-as-march-mcpu.s

43

Below you have a comment (cortex-a32 is armv8a). That is very helpful for me. I assume cortex-a8 is armv7a?

44

I guess -check-prefix is accepted with one or two leading hyphens. Let's pick one style to use consistently in this test.

83

add a -mcpu=foo,bar test for -mcpu? (Comma separated)

95

add a comma separated test? (-march=armv8-a,armv7-a)

clang/test/Driver/arm-target-as-mthumb.s

9–17

Should we add space separated tests for these? -Wa,-mcpu=cortex-a8 -Wa,-mthumb?

[nickdesaulniers]

clang/test/Driver/arm-target-as-march-mcpu.s

43

And if so, would you mind adding a similar comment here?

[DavidSpickett]

• Added split -Wa test for -mthumb
• Use --check-prefix/--check-prefixes
• Comment at top of march/mcpu file to explain choice of test CPUs

[DavidSpickett]

clang/test/Driver/arm-target-as-march-mcpu.s

43

Exactly, I've added a comment up top to explain the logic in one place.

83

mcpu and march don't let you use multiple values:

error: the clang compiler does not support '-march=armv8-a,armv7-a'
error: unsupported argument 'armv7-a' to option 'Wa,

(the latter it thinks that its another arg like -Wa,armv7-a)

Pretty sure that's tested elsewhere or if it isn't, this isn't the place for it at least.

[nickdesaulniers]

Looks great. Thanks again David.

clang/lib/Driver/ToolChain.cpp

case llvm::Triple::thumbeb: {
     if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
       MCPU = A->getValue();
     if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
       MArch = A->getValue();
     std::string CPU =
         Triple.isOSBinFormatMachO()
             ? tools::arm::getARMCPUForMArch(MArch, Triple).str()
             : tools::arm::getARMTargetCPU(MCPU, MArch, Triple);
     StringRef Suffix =
       tools::arm::getLLVMArchSuffixForARM(CPU, MArch, Triple);
     bool IsMProfile = ARM::parseArchProfile(Suffix) == ARM::ProfileKind::M;
     bool ThumbDefault = IsMProfile || (ARM::parseArchVersion(Suffix) == 7 &&
                                        getTriple().isOSBinFormatMachO());
     // FIXME: this is invalid for WindowsCE
     if (getTriple().isOSWindows())
       ThumbDefault = true;
     std::string ArchName;
case llvm::Triple::thumbeb: {
     // passed to the assembler via -Wa or -Xassembler.
     bool IsThumb = false;
     if (InputType != types::TY_PP_Asm)
       IsThumb = Args.hasFlag(options::OPT_mthumb, options::OPT_mno_thumb,
                               ThumbDefault);
     else {
       // Ideally we would check for these flags in
       // CollectArgsForIntegratedAssembler but we can't change the ArchName at
-      // that point. There is no assembler equivalent of -mno-thumb, -marm, or
-      // -mno-arm.
+      // that point.
+      llvm::StringRef WaMArch, WaMCPU;
       for (const auto *A :
            Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler)) {
         for (StringRef Value : A->getValues()) {
+          // There is no assembler equivalent of -mno-thumb, -marm, or -mno-arm.
           if (Value == "-mthumb")
             IsThumb = true;
+          else if (Value.startswith("-march="))
+            WaMArch = Value.substr(7);
+          else if (Value.startswith("-mcpu="))
+            WaMCPU = Value.substr(6);
         }
       }
+
+      if (WaMCPU.size() || WaMArch.size()) {
+        // The way this works means that we prefer -Wa,-mcpu's architecture
+        // over -Wa,-march. Which matches the compiler behaviour.
+        Suffix = tools::arm::getLLVMArchSuffixForARM(WaMCPU, WaMArch, Triple);
+      }
     }
     // Assembly files should start in ARM mode, unless arch is M-profile, or
     // -mthumb has been passed explicitly to the assembler. Windows is always
     // thumb.
     if (IsThumb || IsMProfile || getTriple().isOSWindows()) {
       if (IsBigEndian)
         ArchName = "thumbeb";
       else

clang/lib/Driver/ToolChains/Arch/ARM.cpp

if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_mcpu_EQ))
     CPU = A->getValue();
   if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
     Arch = A->getValue();
   if (!FromAs)
     return;
 
   for (const Arg *A :
        Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler)) {
-    StringRef Value = A->getValue();
+    // Use getValues because -Wa can have multiple arguments
+    // e.g. -Wa,-mcpu=foo,-mcpu=bar
+    for (StringRef Value : A->getValues()) {
       if (Value.startswith("-mcpu="))
         CPU = Value.substr(6);
       if (Value.startswith("-march="))
         Arch = Value.substr(7);
     }
   }
+}
 
 // Handle -mhwdiv=.
 // FIXME: Use ARMTargetParser.
 static void getARMHWDivFeatures(const Driver &D, const Arg *A,
                                 const ArgList &Args, StringRef HWDiv,
                                 std::vector<StringRef> &Features) {
   uint64_t HWDivID = llvm::ARM::parseHWDiv(HWDiv);
   if (!llvm::ARM::getHWDivFeatures(HWDivID, Features))

 
 void arm::getARMTargetFeatures(const Driver &D, const llvm::Triple &Triple,
                                const ArgList &Args, ArgStringList &CmdArgs,
                                std::vector<StringRef> &Features, bool ForAS) {
   bool KernelOrKext =
       Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
   arm::FloatABI ABI = arm::getARMFloatABI(D, Triple, Args);
   arm::ReadTPMode ThreadPointer = arm::getReadTPMode(D, Args);
-  const Arg *WaCPU = nullptr, *WaFPU = nullptr;
-  const Arg *WaHDiv = nullptr, *WaArch = nullptr;
+  llvm::Optional<std::pair<const Arg *, StringRef>> WaCPU, WaFPU, WaHDiv,
+      WaArch;
 
   // This vector will accumulate features from the architecture
   // extension suffixes on -mcpu and -march (e.g. the 'bar' in
   // -mcpu=foo+bar). We want to apply those after the features derived
   // from the FPU, in case -mfpu generates a negative feature which
   // the +bar is supposed to override.
   std::vector<StringRef> ExtensionFeatures;
 
if (!ForAS) {
     // Use software floating point argument passing?
     if (ABI != arm::FloatABI::Hard)
       Features.push_back("+soft-float-abi");
   } else {
     // Here, we make sure that -Wa,-mfpu/cpu/arch/hwdiv will be passed down
     // to the assembler correctly.
     for (const Arg *A :
          Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler)) {
-      StringRef Value = A->getValue();
+      // We use getValues here because you can have many options per -Wa
+      // We will keep the last one we find for each of these
+      for (StringRef Value : A->getValues()) {
         if (Value.startswith("-mfpu=")) {
-        WaFPU = A;
+          WaFPU = std::make_pair(A, Value.substr(6));
         } else if (Value.startswith("-mcpu=")) {
-        WaCPU = A;
+          WaCPU = std::make_pair(A, Value.substr(6));
         } else if (Value.startswith("-mhwdiv=")) {
-        WaHDiv = A;
+          WaHDiv = std::make_pair(A, Value.substr(8));
         } else if (Value.startswith("-march=")) {
-        WaArch = A;
+          WaArch = std::make_pair(A, Value.substr(7));
+        }
       }
     }
   }
 
   if (ThreadPointer == arm::ReadTPMode::Cp15)
     Features.push_back("+read-tp-hard");
 
   const Arg *ArchArg = Args.getLastArg(options::OPT_march_EQ);
   const Arg *CPUArg = Args.getLastArg(options::OPT_mcpu_EQ);
   StringRef ArchName;
   StringRef CPUName;
   unsigned ArchArgFPUID = llvm::ARM::FK_INVALID;
   unsigned CPUArgFPUID = llvm::ARM::FK_INVALID;
 
   // Check -mcpu. ClangAs gives preference to -Wa,-mcpu=.
   if (WaCPU) {
     if (CPUArg)
       D.Diag(clang::diag::warn_drv_unused_argument)
           << CPUArg->getAsString(Args);
-    CPUName = StringRef(WaCPU->getValue()).substr(6);
-    CPUArg = WaCPU;
+    CPUName = WaCPU->second;
+    CPUArg = WaCPU->first;
   } else if (CPUArg)
     CPUName = CPUArg->getValue();
 
   // Check -march. ClangAs gives preference to -Wa,-march=.
   if (WaArch) {
     if (ArchArg)
       D.Diag(clang::diag::warn_drv_unused_argument)
           << ArchArg->getAsString(Args);
-    ArchName = StringRef(WaArch->getValue()).substr(7);
-    checkARMArchName(D, WaArch, Args, ArchName, CPUName, ExtensionFeatures,
-                     Triple, ArchArgFPUID);
-    // FIXME: Set Arch.
-    D.Diag(clang::diag::warn_drv_unused_argument) << WaArch->getAsString(Args);
+    ArchName = WaArch->second;
+    // This will set any features after the base architecture.
+    checkARMArchName(D, WaArch->first, Args, ArchName, CPUName,
+                     ExtensionFeatures, Triple, ArchArgFPUID);
+    // The base architecture was handled in ToolChain::ComputeLLVMTriple because
+    // triple is read only by this point.
   } else if (ArchArg) {
     ArchName = ArchArg->getValue();
     checkARMArchName(D, ArchArg, Args, ArchName, CPUName, ExtensionFeatures,
                      Triple, ArchArgFPUID);
   }
 
   // Add CPU features for generic CPUs
   if (CPUName == "native") {
checkARMCPUName(D, CPUArg, Args, CPUName, ArchName, ExtensionFeatures,
                     Triple, CPUArgFPUID);
   // Honor -mfpu=. ClangAs gives preference to -Wa,-mfpu=.
   unsigned FPUID = llvm::ARM::FK_INVALID;
   const Arg *FPUArg = Args.getLastArg(options::OPT_mfpu_EQ);
   if (WaFPU) {
     if (FPUArg)
       D.Diag(clang::diag::warn_drv_unused_argument)
           << FPUArg->getAsString(Args);
-    (void)getARMFPUFeatures(D, WaFPU, Args, StringRef(WaFPU->getValue()).substr(6),
-                            Features);
+    (void)getARMFPUFeatures(D, WaFPU->first, Args, WaFPU->second, Features);
   } else if (FPUArg) {
     FPUID = getARMFPUFeatures(D, FPUArg, Args, FPUArg->getValue(), Features);
   } else if (Triple.isAndroid() && getARMSubArchVersionNumber(Triple) >= 7) {
     const char *AndroidFPU = "neon";
     FPUID = llvm::ARM::parseFPU(AndroidFPU);
     if (!llvm::ARM::getFPUFeatures(FPUID, Features))
       D.Diag(clang::diag::err_drv_clang_unsupported)
           << std::string("-mfpu=") + AndroidFPU;
   }
 
   // Now we've finished accumulating features from arch, cpu and fpu,
   // we can append the ones for architecture extensions that we
   // collected separately.
   Features.insert(std::end(Features),
                   std::begin(ExtensionFeatures), std::end(ExtensionFeatures));
 
   // Honor -mhwdiv=. ClangAs gives preference to -Wa,-mhwdiv=.
   const Arg *HDivArg = Args.getLastArg(options::OPT_mhwdiv_EQ);
   if (WaHDiv) {
     if (HDivArg)
       D.Diag(clang::diag::warn_drv_unused_argument)
           << HDivArg->getAsString(Args);
-    getARMHWDivFeatures(D, WaHDiv, Args,
-                        StringRef(WaHDiv->getValue()).substr(8), Features);
+    getARMHWDivFeatures(D, WaHDiv->first, Args, WaHDiv->second, Features);
   } else if (HDivArg)
     getARMHWDivFeatures(D, HDivArg, Args, HDivArg->getValue(), Features);
 
   // Handle (arch-dependent) fp16fml/fullfp16 relationship.
   // Must happen before any features are disabled due to soft-float.
   // FIXME: this fp16fml option handling will be reimplemented after the
   // TargetParser rewrite.
   const auto ItRNoFullFP16 = std::find(Features.rbegin(), Features.rend(), "-fullfp16");

clang/test/Driver/arm-target-as-march-mcpu.s

+/// These tests make sure that options passed to the assembler
+/// via -Wa or -Xassembler are applied correctly to assembler inputs.
+/// Also we check that the same priority rules apply to compiler and
+/// assembler options.
+///
+/// Note that the cortex-a8 is armv7-a, the cortex-a32 is armv8-a
+/// and clang's default Arm architecture is armv4t.
+
+/// Sanity check how the options behave when passed to the compiler
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv7-a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv7-a+crc %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,EXT-CRC %s
+
+/// -Wa/-Xassembler doesn't apply to non assembly files
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-march=armv7-a \
+// RUN: %S/Inputs/wildcard1.c 2>&1 | FileCheck --check-prefix=TRIPLE-ARMV4 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Xassembler -march=armv7-a \
+// RUN: %S/Inputs/wildcard1.c 2>&1 | FileCheck --check-prefix=TRIPLE-ARMV4 %s
+
+/// -Wa/-Xassembler does apply to assembler input
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-march=armv7-a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-march=armv7-a+crc %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,EXT-CRC %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Xassembler -march=armv7-a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Xassembler -march=armv7-a+crc %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,EXT-CRC %s
+
+/// Check that arch name is still canonicalised
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-march=armv7a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Xassembler -march=armv7 %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+
+/// march to compiler and assembler, we choose the one suited to the input file type
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv8-a -Wa,-march=armv7a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv7-a -Wa,-march=armv8-a \
+// RUN: %S/Inputs/wildcard1.c 2>&1 | FileCheck --check-prefix=TRIPLE-ARMV7 %s
+
+/// mcpu to compiler and march to assembler, we use the assembler's architecture for assembly files.
+/// We use the target CPU for both.
+// RUN: %clang -target arm-linux-gnueabi -### -c -mcpu=cortex-a8 -Wa,-march=armv8a %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV8,CPU-A8 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -mcpu=cortex-a8 -Wa,-march=armv8-a \
+// RUN: %S/Inputs/wildcard1.c 2>&1 | FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+
+/// march to compiler and mcpu to assembler, we use the one that matches the file type
+/// (again both get the target-cpu option either way)
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv8a -Wa,-mcpu=cortex-a8 %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv8a -Wa,-mcpu=cortex-a8 \
+// RUN: %S/Inputs/wildcard1.c 2>&1 | FileCheck --check-prefix=TRIPLE-ARMV8 %s
+
+/// march and mcpu to the compiler, mcpu wins
+// RUN: %clang -target arm-linux-gnueabi -### -c -mcpu=cortex-a8 -march=armv8-a %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+/// not dependent on order
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv8-a -mcpu=cortex-a8 %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+/// or file type
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv8a -mcpu=cortex-a8 \
+// RUN: %S/Inputs/wildcard1.c 2>&1 | FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+
+/// If we pass mcpu and march to the assembler then mcpu's arch wins
+/// (matches the compiler behaviour)
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-mcpu=cortex-a8 -Wa,-march=armv8-a %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-mcpu=cortex-a8,-march=armv8-a %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Xassembler -march=armv8-a -Xassembler -mcpu=cortex-a8 \
+// RUN: %s 2>&1 | FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+
+/// Last mcpu to assembler wins
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-mcpu=cortex-a32,-mcpu=cortex-a8 %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-mcpu=cortex-a32 -Wa,-mcpu=cortex-a8 %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 --check-prefix=CPU-A8 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Xassembler -mcpu=cortex-a32 -Xassembler -mcpu=cortex-a8 \
+// RUN: %s 2>&1 | FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+
+/// Last mcpu to compiler wins
+// RUN: %clang -target arm-linux-gnueabi -### -c -mcpu=cortex-a32 -mcpu=cortex-a8 %s 2>&1 | \
+// RUN: FileCheck --check-prefixes=TRIPLE-ARMV7,CPU-A8 %s
+
+/// Last march to assembler wins
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-march=armv8-a,-march=armv7-a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Wa,-march=armv8-a -Wa,-march=armv7-a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+// RUN: %clang -target arm-linux-gnueabi -### -c -Xassembler -march=armv8-a -Xassembler -march=armv7-a \
+// RUN: %s 2>&1 | FileCheck --check-prefix=TRIPLE-ARMV7 %s
+
+/// Last march to compiler wins
+// RUN: %clang -target arm-linux-gnueabi -### -c -march=armv8-a -march=armv7-a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-ARMV7 %s
+
+// TRIPLE-ARMV4: "-triple" "armv4t-unknown-linux-gnueabi"
+// TRIPLE-ARMV7: "-triple" "armv7-unknown-linux-gnueabi"
+// TRIPLE-ARMV8: "-triple" "armv8-unknown-linux-gnueabi"
+// CPU-A8: "-target-cpu" "cortex-a8"
+// EXT-CRC: "-target-feature" "+crc"

clang/test/Driver/arm-target-as-mthumb.s

 // Make sure -mthumb does not affect assembler triple, but -Wa,-mthumb or
 // -Xassembler -mthumb does. Also check that -Wa,-mthumb or -Xassembler -mthumb
 // does not affect non assembler files.
 
 // RUN: %clang -target armv7a-linux-gnueabi -### -c -mthumb %s 2>&1 | \
 // RUN: FileCheck -check-prefix=TRIPLE-ARM %s
 // RUN: %clang -target armv7a-linux-gnueabi -### -c -Wa,-mthumb \
-// RUN: %S/Inputs/wildcard1.c  2>&1 | FileCheck -check-prefix=TRIPLE-ARM %s
+// RUN: %S/Inputs/wildcard1.c 2>&1 | FileCheck -check-prefix=TRIPLE-ARM %s
+// RUN: %clang -target armv7a-linux-gnueabi -### -c -Wa,-mcpu=cortex-a8,-mthumb \
+// RUN: %S/Inputs/wildcard1.c 2>&1 | FileCheck -check-prefix=TRIPLE-ARM %s
 
 // TRIPLE-ARM: "-triple" "armv7-unknown-linux-gnueabi"
 
 // RUN: %clang -target armv7a-linux-gnueabi -### -c -Wa,-mthumb %s 2>&1 | \
 // RUN: FileCheck -check-prefix=TRIPLE-THUMB %s
+// RUN: %clang -target armv7a-linux-gnueabi -### -c -Wa,-mcpu=cortex-a8,-mthumb %s 2>&1 | \
+// RUN: FileCheck -check-prefix=TRIPLE-THUMB %s
+// RUN: %clang -target armv7a-linux-gnueabi -### -c -Wa,-mcpu=cortex-a8 -Wa,-mthumb %s 2>&1 | \
+// RUN: FileCheck -check-prefix=TRIPLE-THUMB %s
 // RUN: %clang -target armv7a-linux-gnueabi -### -c -Xassembler -mthumb %s \
 // RUN: 2>&1 | FileCheck -check-prefix=TRIPLE-THUMB %s
 
 // TRIPLE-THUMB: "-triple" "thumbv7-unknown-linux-gnueabi"