<p dir="ltr">Ping? Can you answer this?</p>
<div class="gmail_quote">On Nov 1, 2013 3:04 PM, "Eric Christopher" <<a href="mailto:echristo@gmail.com">echristo@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Out of curiosity this seems to be enshrining for AArch64 the -march/-mcpu stuff from the old 32-bit arm gcc port. Why is this necessary? Why not just -march=cortex-a53 to generate code for a particular architecture and -mtune=cortex-a53 to tune, but not use any cpu specific instructions for a particular architecture? Can you explain what your thoughts are here?<div>
<br></div><div>-eric</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Oct 31, 2013 at 2:32 AM, Amara Emerson <span dir="ltr"><<a href="mailto:amara.emerson@arm.com" target="_blank">amara.emerson@arm.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: aemerson<br>
Date: Thu Oct 31 04:32:33 2013<br>
New Revision: 193740<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=193740&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=193740&view=rev</a><br>
Log:<br>
[AArch64] Add some CPU targets for "generic", A-53 and A-57.<br>
<br>
Enables the clang driver to begin targeting specific CPUs. Introduced a<br>
"generic" CPU which will ensure that the optional FP feature is enabled<br>
by default when it gets to LLVM, without needing any extra arguments.<br>
Cortex-A53 and A-57 are also introduced with tests, although backend<br>
handling of them does not yet exist.<br>
<br>
Added:<br>
cfe/trunk/test/Driver/aarch64-cpus.c<br>
cfe/trunk/test/Driver/aarch64-mfpu.c<br>
Modified:<br>
cfe/trunk/lib/Basic/Targets.cpp<br>
cfe/trunk/lib/Driver/Tools.cpp<br>
cfe/trunk/lib/Driver/Tools.h<br>
<br>
Modified: cfe/trunk/lib/Basic/Targets.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets.cpp?rev=193740&r1=193739&r2=193740&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets.cpp?rev=193740&r1=193739&r2=193740&view=diff</a><br>
==============================================================================<br>
--- cfe/trunk/lib/Basic/Targets.cpp (original)<br>
+++ cfe/trunk/lib/Basic/Targets.cpp Thu Oct 31 04:32:33 2013<br>
@@ -3472,6 +3472,13 @@ public:<br>
return Feature == "aarch64" || (Feature == "neon" && FPU == NeonMode);<br>
}<br>
<br>
+ virtual bool setCPU(const std::string &Name) {<br>
+ return llvm::StringSwitch<bool>(Name)<br>
+ .Case("generic", true)<br>
+ .Cases("cortex-a53", "cortex-a57", true)<br>
+ .Default(false);<br>
+ }<br>
+<br>
virtual bool handleTargetFeatures(std::vector<std::string> &Features,<br>
DiagnosticsEngine &Diags) {<br>
FPU = FPUMode;<br>
<br>
Modified: cfe/trunk/lib/Driver/Tools.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=193740&r1=193739&r2=193740&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=193740&r1=193739&r2=193740&view=diff</a><br>
==============================================================================<br>
--- cfe/trunk/lib/Driver/Tools.cpp (original)<br>
+++ cfe/trunk/lib/Driver/Tools.cpp Thu Oct 31 04:32:33 2013<br>
@@ -539,6 +539,26 @@ static std::string getARMTargetCPU(const<br>
.Default("arm7tdmi");<br>
}<br>
<br>
+/// getAArch64TargetCPU - Get the (LLVM) name of the AArch64 cpu we are targeting.<br>
+//<br>
+// FIXME: tblgen this.<br>
+static std::string getAArch64TargetCPU(const ArgList &Args,<br>
+ const llvm::Triple &Triple) {<br>
+ // FIXME: Warn on inconsistent use of -mcpu and -march.<br>
+<br>
+ // If we have -mcpu=, use that.<br>
+ if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {<br>
+ StringRef MCPU = A->getValue();<br>
+ // Handle -mcpu=native.<br>
+ if (MCPU == "native")<br>
+ return llvm::sys::getHostCPUName();<br>
+ else<br>
+ return MCPU;<br>
+ }<br>
+<br>
+ return "generic";<br>
+}<br>
+<br>
// FIXME: Move to target hook.<br>
static bool isSignedCharDefault(const llvm::Triple &Triple) {<br>
switch (Triple.getArch()) {<br>
@@ -1304,6 +1324,9 @@ static std::string getCPUName(const ArgL<br>
default:<br>
return "";<br>
<br>
+ case llvm::Triple::aarch64:<br>
+ return getAArch64TargetCPU(Args, T);<br>
+<br>
case llvm::Triple::arm:<br>
case llvm::Triple::thumb:<br>
return getARMTargetCPU(Args, T);<br>
<br>
Modified: cfe/trunk/lib/Driver/Tools.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.h?rev=193740&r1=193739&r2=193740&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.h?rev=193740&r1=193739&r2=193740&view=diff</a><br>
==============================================================================<br>
--- cfe/trunk/lib/Driver/Tools.h (original)<br>
+++ cfe/trunk/lib/Driver/Tools.h Thu Oct 31 04:32:33 2013<br>
@@ -49,6 +49,8 @@ using llvm::opt::ArgStringList;<br>
const InputInfo &Output,<br>
const InputInfoList &Inputs) const;<br>
<br>
+ void AddAArch64TargetArgs(const llvm::opt::ArgList &Args,<br>
+ llvm::opt::ArgStringList &CmdArgs) const;<br>
void AddARMTargetArgs(const llvm::opt::ArgList &Args,<br>
llvm::opt::ArgStringList &CmdArgs,<br>
bool KernelOrKext) const;<br>
<br>
Added: cfe/trunk/test/Driver/aarch64-cpus.c<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/aarch64-cpus.c?rev=193740&view=auto" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/aarch64-cpus.c?rev=193740&view=auto</a><br>
==============================================================================<br>
--- cfe/trunk/test/Driver/aarch64-cpus.c (added)<br>
+++ cfe/trunk/test/Driver/aarch64-cpus.c Thu Oct 31 04:32:33 2013<br>
@@ -0,0 +1,10 @@<br>
+// Check target CPUs are correctly passed.<br>
+<br>
+// RUN: %clang -target aarch64 -### -c %s 2>&1 | FileCheck -check-prefix=GENERIC %s<br>
+// GENERIC: "-cc1"{{.*}} "-triple" "aarch64" {{.*}} "-target-cpu" "generic"<br>
+<br>
+// RUN: %clang -target aarch64 -mcpu=cortex-a53 -### -c %s 2>&1 | FileCheck -check-prefix=CA53 %s<br>
+// CA53: "-cc1"{{.*}} "-triple" "aarch64" {{.*}} "-target-cpu" "cortex-a53"<br>
+<br>
+// RUN: %clang -target aarch64 -mcpu=cortex-a57 -### -c %s 2>&1 | FileCheck -check-prefix=CA57 %s<br>
+// CA57: "-cc1"{{.*}} "-triple" "aarch64" {{.*}} "-target-cpu" "cortex-a57"<br>
<br>
Added: cfe/trunk/test/Driver/aarch64-mfpu.c<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/aarch64-mfpu.c?rev=193740&view=auto" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/aarch64-mfpu.c?rev=193740&view=auto</a><br>
==============================================================================<br>
--- cfe/trunk/test/Driver/aarch64-mfpu.c (added)<br>
+++ cfe/trunk/test/Driver/aarch64-mfpu.c Thu Oct 31 04:32:33 2013<br>
@@ -0,0 +1,26 @@<br>
+// Test that different values of -mfpu pick correct AArch64 FPU target-feature(s).<br>
+<br>
+// RUN: %clang -target aarch64-linux-eabi -mfpu=neon %s -### -o %t.o 2>&1 \<br>
+// RUN: | FileCheck --check-prefix=CHECK-NEON %s<br>
+// CHECK-NEON: "-target-feature" "+neon"<br>
+<br>
+// RUN: %clang -target aarch64-linux-eabi -mfpu=fp-armv8 %s -### -o %t.o 2>&1 \<br>
+// RUN: | FileCheck --check-prefix=CHECK-FP-ARMV8 %s<br>
+// CHECK-FP-ARMV8: "-target-feature" "+fp-armv8"<br>
+<br>
+// RUN: %clang -target aarch64-linux-eabi -mfpu=neon-fp-armv8 %s -### 2>&1 \<br>
+// RUN: | FileCheck --check-prefix=CHECK-NEON-FP-ARMV8 %s<br>
+// CHECK-NEON-FP-ARMV8: "-target-feature" "+fp-armv8"<br>
+// CHECK-NEON-FP-ARMV8: "-target-feature" "+neon"<br>
+<br>
+// RUN: %clang -target aarch64-linux-eabi -mfpu=crypto-neon-fp-armv8 %s -### 2>&1 \<br>
+// RUN: | FileCheck --check-prefix=CHECK-CRYPTO-NEON-FP-ARMV8 %s<br>
+// CHECK-CRYPTO-NEON-FP-ARMV8: "-target-feature" "+fp-armv8"<br>
+// CHECK-CRYPTO-NEON-FP-ARMV8: "-target-feature" "+neon"<br>
+// CHECK-CRYPTO-NEON-FP-ARMV8: "-target-feature" "+crypto"<br>
+<br>
+// RUN: %clang -target aarch64-linux-eabi -mfpu=none %s -### 2>&1 \<br>
+// RUN: | FileCheck --check-prefix=CHECK-NO-FP %s<br>
+// CHECK-NO-FP: "-target-feature" "-fp-armv8"<br>
+// CHECK-NO-FP: "-target-feature" "-crypto"<br>
+// CHECK-NO-FP: "-target-feature" "-neon"<br>
<br>
<br>
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</blockquote></div><br></div>
</blockquote></div>