[AVR] Add support for the -mdouble=x flag

This flag is used by avr-gcc (starting with v10) to set the width of the
double type. The double type is by default interpreted as a 32-bit
floating point number in avr-gcc instead of a 64-bit floating point
number as is common on other architectures. Starting with GCC 10, a new
option has been added to control this behavior:
https://gcc.gnu.org/wiki/avr-gcc#Deviations_from_the_Standard

This commit keeps the default double at 32 bits but adds support for the
-mdouble flag (-mdouble=32 and -mdouble=64) to control this behavior.

Differential Revision: https://reviews.llvm.org/D76181

1 files changed, 1 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 08a0b98..e2b24f0 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2937,6 +2937,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.PackStruct = getLastArgIntValue(Args, OPT_fpack_struct_EQ, 0, Diags);
   Opts.MaxTypeAlign = getLastArgIntValue(Args, OPT_fmax_type_align_EQ, 0, Diags);
   Opts.AlignDouble = Args.hasArg(OPT_malign_double);
+  Opts.DoubleSize = getLastArgIntValue(Args, OPT_mdouble_EQ, 0, Diags);
   Opts.LongDoubleSize = Args.hasArg(OPT_mlong_double_128)
                             ? 128
                             : Args.hasArg(OPT_mlong_double_64) ? 64 : 0;