[llvm-bugs] [Bug 45722] New: [X86] Using SSE4 instructions for roundl() cause test failure in Android.

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=45722

            Bug ID: 45722
           Summary: [X86] Using SSE4 instructions for roundl() cause test
                    failure in Android.
           Product: new-bugs
           Version: unspecified
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: new bugs
          Assignee: unassignedbugs at nondot.org
          Reporter: yabinc at google.com
                CC: htmldeveloper at gmail.com, llvm-bugs at lists.llvm.org

With patch https://reviews.llvm.org/D73607 ([X86] Custom lower ISD::FROUND with
SSE4.1 to avoid a libcall), we have a problem to pass a test in Android.

The test is TEST(MATH_TEST, roundl) in
https://android.googlesource.com/platform/bionic/+/refs/heads/master/tests/math_test.cpp#1224.

The problem is: with the LLVM patch, roundl(0.5L) is replace by SSE
instructions when building for 32-bit tests on x86_64. And SSE instructions are
affected by round mode set by fesetround(FE_TOWARDZERO), and makes roundl(0.5L)
=> 0.

I am not sure where we should fix this (Android bionic libc or llvm). So create
this bug to ask for help.

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