From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Wed, 14 Dec 2011 21:02:23 +0000 (+0000)
Subject: Don't use the frame pointer on linux x86 and x86_64 if optimizing. This
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6af27ec69560f7e4b0dac4a0b4341cd6062f6852;p=clang

Don't use the frame pointer on linux x86 and x86_64 if optimizing. This
matches gcc's behavior.

Fixes PR8186.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146586 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 50b9b418e1..68edd66f5f 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1195,6 +1195,24 @@ static void addAsanRTLinux(const ToolChain &TC, const ArgList &Args,
   CmdArgs.push_back("-export-dynamic");
 }
 
+static bool shouldUseFramePointer(const ArgList &Args,
+                                  const llvm::Triple &Triple) {
+  if (Arg *A = Args.getLastArg(options::OPT_fno_omit_frame_pointer,
+                               options::OPT_fomit_frame_pointer))
+    return A->getOption().matches(options::OPT_fno_omit_frame_pointer);
+
+  // Don't use a frame poiter on liunx x86 and x86_64 if optimizing.
+  if ((Triple.getArch() == llvm::Triple::x86_64 ||
+       Triple.getArch() == llvm::Triple::x86) &&
+      Triple.getOS() == llvm::Triple::Linux) {
+    if (Arg *A = Args.getLastArg(options::OPT_O_Group))
+      if (!A->getOption().matches(options::OPT_O0))
+        return false;
+  }
+
+  return true;
+}
+
 void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                          const InputInfo &Output,
                          const InputInfoList &Inputs,
@@ -1408,8 +1426,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-mrtd");
 
   // FIXME: Set --enable-unsafe-fp-math.
-  if (Args.hasFlag(options::OPT_fno_omit_frame_pointer,
-                   options::OPT_fomit_frame_pointer))
+  if (shouldUseFramePointer(Args, getToolChain().getTriple()))
     CmdArgs.push_back("-mdisable-fp-elim");
   if (!Args.hasFlag(options::OPT_fzero_initialized_in_bss,
                     options::OPT_fno_zero_initialized_in_bss))
diff --git a/test/Driver/frame-pointer.c b/test/Driver/frame-pointer.c
new file mode 100644
index 0000000000..da72ec23c7
--- /dev/null
+++ b/test/Driver/frame-pointer.c
@@ -0,0 +1,24 @@
+// RUN: %clang -ccc-host-triple i386-pc-linux -### -S -O0 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK0-32 %s
+// RUN: %clang -ccc-host-triple i386-pc-linux -### -S -O1 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK1-32 %s
+// RUN: %clang -ccc-host-triple i386-pc-linux -### -S -O2 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK2-32 %s
+// RUN: %clang -ccc-host-triple i386-pc-linux -### -S -O3 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK3-32 %s
+// RUN: %clang -ccc-host-triple i386-pc-linux -### -S -Os %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECKs-32 %s
+
+
+// RUN: %clang -ccc-host-triple x86_64-pc-linux -### -S -O0 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK0-64 %s
+// RUN: %clang -ccc-host-triple x86_64-pc-linux -### -S -O1 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK1-64 %s
+// RUN: %clang -ccc-host-triple x86_64-pc-linux -### -S -O2 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK2-64 %s
+// RUN: %clang -ccc-host-triple x86_64-pc-linux -### -S -O3 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK3-64 %s
+// RUN: %clang -ccc-host-triple x86_64-pc-linux -### -S -Os %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECKs-64 %s
+
+// CHECK0-32: -mdisable-fp-elim
+// CHECK1-32-NOT: -mdisable-fp-elim
+// CHECK2-32-NOT: -mdisable-fp-elim
+// CHECK3-32-NOT: -mdisable-fp-elim
+// CHECKs-32-NOT: -mdisable-fp-elim
+
+// CHECK0-64: -mdisable-fp-elim
+// CHECK1-64-NOT: -mdisable-fp-elim
+// CHECK2-64-NOT: -mdisable-fp-elim
+// CHECK3-64-NOT: -mdisable-fp-elim
+// CHECKs-64-NOT: -mdisable-fp-elim