floating-point operations have side effects

[sunfishcode]

Bugzilla Link	6050
Version	unspecified
OS	All
CC	@andykaylor,@chfast,@lattner,@DimitryAndric,@emaste,@thielema,@nlewycky,@rotateright,@vinc17fr,@yuanfang-chen,@ZviRackover

Extended Description

Floating-point instructions, such as add, sub, mul, and div, as well as math library functions in -fno-math-errno mode, are considered to have no side effects in LLVM. This is incorrect; they may set floating-point exception flags, and they may trap if the processor is configured to trap on floating-point exceptions.

As a consequence of this, these side effects may be reordered or eliminated by the optimizer and codegen.

[sunfishcode]

*** Bug llvm/llvm-bugzilla-archive#6393 has been marked as a duplicate of this bug. ***

[efriedma-quic]

*** Bug llvm/llvm-bugzilla-archive#11904 has been marked as a duplicate of this bug. ***

[llvmbot]

*** Bug llvm/llvm-bugzilla-archive#23522 has been marked as a duplicate of this bug. ***

[majnemer]

*** Bug llvm/llvm-bugzilla-archive#23707 has been marked as a duplicate of this bug. ***

[DimitryAndric]

*** Bug llvm/llvm-bugzilla-archive#24343 has been marked as a duplicate of this bug. ***

[sunfishcode]

mentioned in issue llvm/llvm-bugzilla-archive#6393