[driver] Improve the implementation of the -Ofast option.
Specifically, allow the flags that fall under this umbrella (i.e., -O3,
-ffast-math, and -fstrict-aliasing) to be overridden/disabled with the
individual -O[0|1|2|s|z]/-fno- flags.
This also fixes the handling of various floating point optimization
flags that are modified by -ffast-math (and thus -Ofast as well).
Part of rdar://13622687
llvm-svn: 180204
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 119b7c7..d93c5cb 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1829,6 +1829,13 @@
C.addCommand(new Command(JA, T, Exec, StripArgs));
}
+static bool isOptimizationLevelFast(const ArgList &Args) {
+ if (Arg *A = Args.getLastArg(options::OPT_O_Group))
+ if (A->getOption().matches(options::OPT_Ofast))
+ return true;
+ return false;
+}
+
void Clang::ConstructJob(Compilation &C, const JobAction &JA,
const InputInfo &Output,
const InputInfoList &Inputs,
@@ -2117,7 +2124,13 @@
if (!Args.hasFlag(options::OPT_fzero_initialized_in_bss,
options::OPT_fno_zero_initialized_in_bss))
CmdArgs.push_back("-mno-zero-initialized-in-bss");
- if (!Args.hasFlag(options::OPT_fstrict_aliasing,
+
+ bool OFastEnabled = isOptimizationLevelFast(Args);
+ // If -Ofast is the optimization level, then -fstrict-aliasing should be
+ // enabled. This alias option is being used to simplify the hasFlag logic.
+ OptSpecifier StrictAliasingAliasOption = OFastEnabled ? options::OPT_Ofast :
+ options::OPT_fstrict_aliasing;
+ if (!Args.hasFlag(options::OPT_fstrict_aliasing, StrictAliasingAliasOption,
options::OPT_fno_strict_aliasing,
getToolChain().IsStrictAliasingDefault()))
CmdArgs.push_back("-relaxed-aliasing");
@@ -2133,13 +2146,18 @@
// Handle segmented stacks.
if (Args.hasArg(options::OPT_fsplit_stack))
CmdArgs.push_back("-split-stacks");
+
+ // If -Ofast is the optimization level, then -ffast-math should be enabled.
+ // This alias option is being used to simplify the getLastArg logic.
+ OptSpecifier FastMathAliasOption = OFastEnabled ? options::OPT_Ofast :
+ options::OPT_ffast_math;
// Handle various floating point optimization flags, mapping them to the
// appropriate LLVM code generation flags. The pattern for all of these is to
// default off the codegen optimizations, and if any flag enables them and no
// flag disables them after the flag enabling them, enable the codegen
// optimization. This is complicated by several "umbrella" flags.
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
options::OPT_fno_fast_math,
options::OPT_ffinite_math_only,
options::OPT_fno_finite_math_only,
@@ -2149,7 +2167,7 @@
A->getOption().getID() != options::OPT_fno_finite_math_only &&
A->getOption().getID() != options::OPT_fhonor_infinities)
CmdArgs.push_back("-menable-no-infs");
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
options::OPT_fno_fast_math,
options::OPT_ffinite_math_only,
options::OPT_fno_finite_math_only,
@@ -2162,7 +2180,7 @@
// -fmath-errno is the default on some platforms, e.g. BSD-derived OSes.
bool MathErrno = getToolChain().IsMathErrnoDefault();
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
options::OPT_fno_fast_math,
options::OPT_fmath_errno,
options::OPT_fno_math_errno))
@@ -2175,7 +2193,7 @@
// entire set of LLVM optimizations, so collect them through all the flag
// madness.
bool AssociativeMath = false;
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
options::OPT_fno_fast_math,
options::OPT_funsafe_math_optimizations,
options::OPT_fno_unsafe_math_optimizations,
@@ -2186,7 +2204,7 @@
A->getOption().getID() != options::OPT_fno_associative_math)
AssociativeMath = true;
bool ReciprocalMath = false;
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
options::OPT_fno_fast_math,
options::OPT_funsafe_math_optimizations,
options::OPT_fno_unsafe_math_optimizations,
@@ -2197,7 +2215,7 @@
A->getOption().getID() != options::OPT_fno_reciprocal_math)
ReciprocalMath = true;
bool SignedZeros = true;
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
options::OPT_fno_fast_math,
options::OPT_funsafe_math_optimizations,
options::OPT_fno_unsafe_math_optimizations,
@@ -2208,7 +2226,7 @@
A->getOption().getID() != options::OPT_fsigned_zeros)
SignedZeros = false;
bool TrappingMath = true;
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
options::OPT_fno_fast_math,
options::OPT_funsafe_math_optimizations,
options::OPT_fno_unsafe_math_optimizations,
@@ -2224,7 +2242,7 @@
// Validate and pass through -fp-contract option.
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
options::OPT_fno_fast_math,
options::OPT_ffp_contract)) {
if (A->getOption().getID() == options::OPT_ffp_contract) {
@@ -2235,7 +2253,8 @@
D.Diag(diag::err_drv_unsupported_option_argument)
<< A->getOption().getName() << Val;
}
- } else if (A->getOption().getID() == options::OPT_ffast_math) {
+ } else if (A->getOption().matches(options::OPT_ffast_math) ||
+ (OFastEnabled && A->getOption().matches(options::OPT_Ofast))) {
// If fast-math is set then set the fp-contract mode to fast.
CmdArgs.push_back(Args.MakeArgString("-ffp-contract=fast"));
}
@@ -2246,9 +2265,10 @@
// preprocessor macros. This is distinct from enabling any optimizations as
// these options induce language changes which must survive serialization
// and deserialization, etc.
- if (Arg *A = Args.getLastArg(options::OPT_ffast_math, options::OPT_fno_fast_math))
- if (A->getOption().matches(options::OPT_ffast_math))
- CmdArgs.push_back("-ffast-math");
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math, FastMathAliasOption,
+ options::OPT_fno_fast_math))
+ if (!A->getOption().matches(options::OPT_fno_fast_math))
+ CmdArgs.push_back("-ffast-math");
if (Arg *A = Args.getLastArg(options::OPT_ffinite_math_only, options::OPT_fno_fast_math))
if (A->getOption().matches(options::OPT_ffinite_math_only))
CmdArgs.push_back("-ffinite-math-only");