[PATCH] D131731: [InstCombine] Remove assumptions about int having 32 bits

[Martin Sebor via Phabricator via llvm-commits]

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The patch submitted in D129915 <https://reviews.llvm.org/D129915> and subsequently committed in rG0dcfe7aa35cd <https://reviews.llvm.org/rG0dcfe7aa35cd4f6dbeb739fcd05f93aa39394f0e> exposes a number of assumptions in `SimplifyLibcalls.cpp` about `int` having 32 bits.  Prior to the change the assumptions, although strictly unsafe, were benign even on 16-bit targets because the validation in `TargetLibraryInfoImpl::isValidProtoForLibFunc` enforced the corresponding restriction.  The change has corrected the function to consider valid on 16-bit targets those functions in whose declarations the `int` return type or argument corresponds to `i16`, but it did not update the corresponding call handlers in `SimplifyLibcalls.cpp`.  The end result is that some valid C code that compiled successfully before the change (albeit with suboptimal output) now causes an abort in the handler when targeting 16-bit environments (AVR or MSP430 in tree).

As a follow-up to D129915 <https://reviews.llvm.org/D129915>, this change removes these 32-bit assumptions to let the same code compile successfully even for 16-bit targets, and to also enable the same optimizing transformations for those targets as for 32-bit ones.

I've tested this patch on x86_64-linux.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D131731

Files:
  llvm/lib/Transforms/Utils/BuildLibCalls.cpp
  llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
  llvm/test/Transforms/InstCombine/ffs-i16.ll
  llvm/test/Transforms/InstCombine/fls-i16.ll
  llvm/test/Transforms/InstCombine/isascii-i16.ll
  llvm/test/Transforms/InstCombine/isdigit-i16.ll
  llvm/test/Transforms/InstCombine/printf-i16.ll
  llvm/test/Transforms/InstCombine/puts-i16.ll

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