[llvm-commits] [PATCH 1/2] Fix PR12312

[Michael Liao]

Hi

This patch is to fix http://llvm.org/bugs/show_bug.cgi?id=12312, where a
special use of i128 needs efficient code generation with PTEST from
SSE4.1.

To fix this issue, 2 patches are developed. The first part is to
simplify a common pattern introduced by most intrinsics generating
boolean values. Their boolean result are re-evaluated again to get
EFLAGS updated for BRCOND/CMOV or even SETCC again to consume. The
attached patch adds a X86-specific DAG optimzation to simplify this
common pattern by directly consuming the EFLAGS updated from the
original intrinsics, e.g. llvm.x86.sse41.ptest, if we found that integer
result is checked as a boolean value.

Yours
- Michael



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