[PATCH] D98895: [X86][Draft] Disable long double type for -mno-x87 option

[Andrew Savonichev via Phabricator via cfe-commits]

asavonic created this revision.
asavonic added a reviewer: andrew.w.kaylor.
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This patch attempts to fix a compiler crash that occurs when `long double` type
is used with `-mno-x87` compiler option.

The option disables x87 target feature, which in turn disables x87 registers, so
CG cannot select them for `x86_fp80` LLVM IR type. Long double is lowered as
`x86_fp80` for some targets, so it leads to a crash.

The option seems to contradict the SystemV ABI, which requires `long double` to
be represented as a 80-bit floating point, and it also requires to use x87 registers.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D98895

Files:
  clang/include/clang/Basic/TargetInfo.h
  clang/lib/Basic/TargetInfo.cpp
  clang/lib/Basic/Targets/X86.cpp
  clang/lib/Basic/Targets/X86.h
  clang/lib/Sema/SemaChecking.cpp
  clang/lib/Sema/SemaDecl.cpp
  clang/lib/Sema/SemaExpr.cpp
  clang/test/Sema/x86-no-x87.c

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