Merge changes from CTSRD main up to 74d200f2bb65b06633ca87f86b1b9145ebf63a46 #272
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resistor
commented
Nov 14, 2025
resistor
commented
- [CodeGen] Don't create combine loops for PTRADD with opaque constants
- Add test for infinite combine fix in the previous commit
- [CodeGen] Use index type for pointer offset in replaceStoreOfInsertLoad
- [AST][Sema] Support unsigned __intcap in getCorrespondingSignedType
- Fix clangd unit test regression.
We were implicitly assuming here that, if one of Y or Z is a constant, either the other is not or we will have already (in the nested PTRADD case) constant-folded both of them into one, and thus don't need to consider the possibility. However, opaque constants exist and do not get constant-folded, so we can end up cycling between PTRADD+ADD and PTRADD+PTRADD. Catch this case by checking the other is not a constant and skipping all but one combine if so. No test is provided since I've yet to be able to trigger it in CHERI LLVM, only downstream in Codasip LLVM and Morello LLVM (and only when targeting CHERI-RISC-V even in Morello LLVM), both of which enable SCEV and thus do interesting loop transformations. Fixes: 05fd67a ("[CodeGen][CHERI-Generic] Support commuting capability offsets when safe")
This was somewhat awkward to reduce since giving the --print-before-all IR to llc would optimize away the pattern that triggers the loop. Writing the test with -start-before=riscv-isel allowed me to reduce it with bugpoint and then manually remove all branches to get the minimal test from this comit
Also use getMemBasePlusOffset rather than a raw ADD since that won't work for capability types either. Fixes: 38e1851 ("[DAGCombine] Fold (store (insert_elt (load p)) x p) -> (store x)")
This is used by the new __make_signed(T) builtin. Note (signed) __intcap is already handled by getCorrespondingUnsignedSignedType from many years ago. Fixes: 1a54ef1 ("[clang] adds unary type transformations as compiler built-ins")
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