[llvm-bugs] [Bug 47782] New: [PowerPC] Clang accepts vector unsigned long long without VSX, miscompiles

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=47782

            Bug ID: 47782
           Summary: [PowerPC] Clang accepts vector unsigned long long
                    without VSX, miscompiles
           Product: clang
           Version: trunk
          Hardware: Other
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: Frontend
          Assignee: unassignedclangbugs at nondot.org
          Reporter: hstong at ca.ibm.com
                CC: llvm-bugs at lists.llvm.org, neeilans at live.com,
                    nemanja.i.ibm at gmail.com, richard-llvm at metafoo.co.uk

GCC treats vector unsigned long long and friends as invalid for AltiVec without
VSX. Clang fails to do so and also fails to use the correct calling convention
when building without VSX.

Compiler Explorer link:
https://godbolt.org/z/n5M1e8

### SOURCE (<stdin>):
double f(vector unsigned long long);

double g(vector unsigned long long *p) {
  return f(*p);
}


### COMPILER INVOCATION:
clang -target powerpc64-unknown-linux-gnu -Wall -Wextra -pedantic-errors -O3
-mcpu=power6 -S -o - -xc -


### ACTUAL ASSEMBLY OUTPUT (snippet):
        ld 4, 8(3)
        ld 3, 0(3)
        bl f


### EXPECTED OUTPUT:
(error message)


### CORRECT VSX ASSEMBLY OUTPUT (snippet):
        lxvd2x 34, 0, 3
        bl f


### COMPILER VERSION INFO (clang -v):
clang version 12.0.0 (https://github.com/llvm/llvm-project.git
68e1a8d20795802077987529e1268c184d749564)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /opt/wandbox/clang-head/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64

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