Commit bbda6e32 authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r325739: 

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r325739 | nemanjai | 2018-02-22 04:02:41 +0100 (Thu, 22 Feb 2018) | 9 lines

[PowerPC] Do not produce invalid CTR loop with an FRem

An FRem instruction inside a loop should prevent the loop from being converted
into a CTR loop since this is not an operation that is legal on any PPC
subtarget. This will always be a call to a library function which means the
loop will be invalid if this instruction is in the body.

Fixes PR36292.

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llvm-svn: 325767
parent 559169d2

llvm/lib/Target/PowerPC/PPCCTRLoops.cpp

+4 −1
Original line number Diff line number Diff line
@@ -454,13 +454,16 @@ bool PPCCTRLoops::mightUseCTR(BasicBlock *BB) { 
        return true;

    }



    // FREM is always a call.

    if (J->getOpcode() == Instruction::FRem)

      return true;



    if (STI->useSoftFloat()) {

      switch(J->getOpcode()) {

      case Instruction::FAdd:

      case Instruction::FSub:

      case Instruction::FMul:

      case Instruction::FDiv:

      case Instruction::FRem:

      case Instruction::FPTrunc:

      case Instruction::FPExt:

      case Instruction::FPToUI:

llvm/test/CodeGen/PowerPC/pr36292.ll

0 → 100644
+46 −0
Original line number Diff line number Diff line 
; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-unknown < %s  | \

; RUN:   FileCheck %s --implicit-check-not=mtctr --implicit-check-not=bdnz

$test = comdat any



; No CTR loop due to frem (since it is always a call).

define void @test() #0 comdat {

; CHECK-LABEL: test:

; CHECK:    ld 29, 0(3)

; CHECK:    ld 30, 40(1)

; CHECK:    xxlxor 31, 31, 31

; CHECK:    cmpld 30, 29

; CHECK-NEXT:    bge- 0, .LBB0_2

; CHECK-NEXT:    .p2align 5

; CHECK-NEXT:  .LBB0_1: # %bounds.ok

; CHECK:    fmr 1, 31

; CHECK-NEXT:    lfsx 2, 0, 3

; CHECK-NEXT:    bl fmodf

; CHECK-NEXT:    nop

; CHECK-NEXT:    addi 30, 30, 1

; CHECK-NEXT:    stfsx 1, 0, 3

; CHECK-NEXT:    cmpld 30, 29

; CHECK-NEXT:    blt+ 0, .LBB0_1

; CHECK-NEXT:  .LBB0_2: # %bounds.fail

; CHECK-NEXT:    std 30, 40(1)

  %pos = alloca i64, align 8

  br label %forcond



forcond:                                          ; preds = %bounds.ok, %0

  %1 = load i64, i64* %pos

  %.len1 = load i64, i64* undef

  %bounds.cmp = icmp ult i64 %1, %.len1

  br i1 %bounds.cmp, label %bounds.ok, label %bounds.fail



bounds.ok:                                        ; preds = %forcond

  %2 = load float, float* undef

  %3 = frem float 0.000000e+00, %2

  store float %3, float* undef

  %4 = load i64, i64* %pos

  %5 = add i64 %4, 1

  store i64 %5, i64* %pos

  br label %forcond



bounds.fail:                                      ; preds = %forcond

  unreachable

}