[llvm-bugs] [Bug 28818] New: powerpc64le: Cannot select AtomicLoadMin

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=28818

            Bug ID: 28818
           Summary: powerpc64le: Cannot select AtomicLoadMin
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: Backend: PowerPC
          Assignee: unassignedbugs at nondot.org
          Reporter: acjacob at us.ibm.com
                CC: llvm-bugs at lists.llvm.org
    Classification: Unclassified

Created attachment 16863
  --> https://llvm.org/bugs/attachment.cgi?id=16863&action=edit
IR that fails to compile through the ppc64le backend.

When compiling the following OpenMP code with a min (or max)-reduction I get a
backend failure with ppc64le because the backend cannot select for LLVM IR
'atomicrmw min'.

#include <stdio.h>
#include <omp.h>

int main(int argc, char *argv[]) {

  int A[2048];
  int n = 2048;

  for (int i = 0; i < n; i++)
    A[i] = i+1;

  int minimum=0;
  #pragma omp parallel reduction(min:minimum)
  {
      minimum += 1;
  }
  printf ("Min=%d\n", minimum);

  return 0;
}


The OpenMP Clang processing generates an 'atomicrmw min' instruction when
codegen'ing for the reduction clause.

%14 = atomicrmw min i32* %0, i32 %13 monotonic

When passing this through the backend I get a failure with the message:

fatal error: error in backend: Cannot select: t7: i32,ch =
AtomicLoadMin<Volatile LDST4[%minimum]> t4:1, t6, t4
  t6: i64,ch = CopyFromReg t0, Register:i64 %vreg3
    t5: i64 = Register %vreg3
  t4: i32,ch = load<LD4[%minimum1](tbaa=<0x1001197c308>)> t0,
FrameIndex:i64<0>, undef:i64
    t1: i64 = FrameIndex<0>
    t3: i64 = undef
In function: .omp_outlined.

I have attached the LLVM IR file with this bug report.  Please let me know if
you need anything else.

Thanks in advance for your time.

Arpith

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20160802/e447ae76/attachment.html>