mibintc added a comment.
Hello, I rebased this and made a few changes here,
https://reviews.llvm.org/D87528 ; I added a question about floating point
constant folding in that review, I'm going to duplicate it here,
My question is about constant folding. I am working on a task to ensure that
clang is doing floating point constant folding correctly. I thought the
constant folding was in AST/ExprConstant.cpp and indeed constant folding does
occur there. But sometimes, if the floating point semantics are set to
'strict', even tho' folding has occurred successfully in ExprConstant.cpp, when
i look at emit-llvm, there is arithmetic emitted for the floating point
expression; For example if you use the command line option
-ffp-exception-behavior=strict and you compile this function, it will emit the
add instruction; but without the option you will see the folded expression.
Either way, if you put a breakpoint inside ExprConstant.cpp the calculation of
the floating sum does occur. The function is float myAdd(void) { return 1.0 +
2.0; }
So where is the decision made that backs out the fold?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D69272/new/
https://reviews.llvm.org/D69272
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