[PATCH] D42154: Don't generate inline atomics for i386/i486

Eli Friedman via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Tue Jan 16 18:10:40 PST 2018

efriedma added a comment.

The LLVM backend currently assumes every CPU is Pentium-compatible.  If we're going to change that in clang, we should probably fix the backend as well.

Comment at: lib/Basic/Targets/X86.h:472
+    CPUKind Kind = getCPUKind(Opts.CPU);
+    if (Kind >= CK_i586 || Kind == CK_Generic)
+      MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 64;
What exactly does "CK_Generic" mean here?  Under what circumstances does it show up? We should have a specific default for every supported target, if user doesn't specify a CPU with -march.

  rC Clang


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