shchenz added a comment.
> This patch turns on support for CR bit accesses for Power8 and above. The
> reason why CR bits are turned on as the default for Power8 and above is that
> because later architectures make use of builtins and instructions that
> require CR bit accesses (such as the use of setbc in the vector string
> isolate predicate and bcd builtins on Power10).
Maybe we also can add some comments in `docs/ClangCommandLineReference.rst` to
explicitly say that `-mcrbits` will be default to on when PowerPC arch is no
smaller than 8. I believe some cr-bit operations also exist on Power7 or even
Power6?
================
Comment at: clang/lib/Basic/Targets/PPC.cpp:519
.Default(false);
+ Features["crbits"] = llvm::StringSwitch<bool>(CPU)
+ .Case("ppc64le", true)
----------------
If we set the `+crbits` by the arch name, do we still need the customization
(Turn on crbits for O2 and above) in `computeFSAdditions()`?
================
Comment at: clang/test/Driver/ppc-crbits.cpp:50
+// RUN: %clang -target powerpc64le-unknown-linux-gnu -mcpu=pwr7 -mno-crbits \
+// RUN: -emit-llvm -S %s -o - | FileCheck %s --check-prefix=HAS-NOCRBITS
+
----------------
Do we need some cases for AIX?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D124060/new/
https://reviews.llvm.org/D124060
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