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[PowerPC] Do not emit HW loop if the body contains calls to lrint/lround 

These two intrinsics are lowered to calls so should prevent the formation of
CTR loops. In a subsequent patch, we will handle all currently known intrinsics
and prevent the formation of HW loops if any unknown intrinsics are encountered.

Differential revision: https://reviews.llvm.org/D68841
This commit is contained in:
Nemanja Ivanovic 2019-10-28 16:08:30 -05:00
parent ad531fff81
commit 97e3626070
2 changed files with 79 additions and 0 deletions
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4
llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
View File

@ -331,8 +331,12 @@ bool PPCTTIImpl::mightUseCTR(BasicBlock *BB,
case Intrinsic::ceil: Opcode = ISD::FCEIL; break;
case Intrinsic::trunc: Opcode = ISD::FTRUNC; break;
case Intrinsic::rint: Opcode = ISD::FRINT; break;
case Intrinsic::lrint: Opcode = ISD::LRINT; break;
case Intrinsic::llrint: Opcode = ISD::LLRINT; break;
case Intrinsic::nearbyint: Opcode = ISD::FNEARBYINT; break;
case Intrinsic::round: Opcode = ISD::FROUND; break;
case Intrinsic::lround: Opcode = ISD::LROUND; break;
case Intrinsic::llround: Opcode = ISD::LLROUND; break;
case Intrinsic::minnum: Opcode = ISD::FMINNUM; break;
case Intrinsic::maxnum: Opcode = ISD::FMAXNUM; break;
case Intrinsic::umul_with_overflow: Opcode = ISD::UMULO; break;

75
llvm/test/CodeGen/PowerPC/pr43527.ll Normal file
View File

@ -0,0 +1,75 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -ppc-asm-full-reg-names -verify-machineinstrs \
; RUN: -mtriple=powerpc64le-unknown-linux-gnu -mcpu=pwr8 < %s | FileCheck %s
; We don't want to produce a CTR loop due to the call to lrint in the body.
define dso_local void @test(i64 %arg, i64 %arg1) {
; CHECK-LABEL: test:
; CHECK: # %bb.0: # %bb
; CHECK-NEXT: bc 4, 4*cr5+lt, .LBB0_5
; CHECK-NEXT: # %bb.1: # %bb3
; CHECK-NEXT: bc 12, 4*cr5+lt, .LBB0_6
; CHECK-NEXT: # %bb.2: # %bb4
; CHECK-NEXT: mflr r0
; CHECK-NEXT: .cfi_def_cfa_offset 64
; CHECK-NEXT: .cfi_offset lr, 16
; CHECK-NEXT: .cfi_offset r29, -24
; CHECK-NEXT: .cfi_offset r30, -16
; CHECK-NEXT: std r29, -24(r1) # 8-byte Folded Spill
; CHECK-NEXT: std r30, -16(r1) # 8-byte Folded Spill
; CHECK-NEXT: std r0, 16(r1)
; CHECK-NEXT: stdu r1, -64(r1)
; CHECK-NEXT: sub r30, r4, r3
; CHECK-NEXT: li r29, 0
; CHECK-NEXT: .p2align 5
; CHECK-NEXT: .LBB0_3: # %bb5
; CHECK-NEXT: #
; CHECK-NEXT: lfsx f1, 0, r29
; CHECK-NEXT: bl lrint
; CHECK-NEXT: nop
; CHECK-NEXT: addi r30, r30, -1
; CHECK-NEXT: addi r29, r29, 4
; CHECK-NEXT: cmpldi r30, 0
; CHECK-NEXT: bne cr0, .LBB0_3
; CHECK-NEXT: # %bb.4: # %bb15
; CHECK-NEXT: stb r3, 0(r3)
; CHECK-NEXT: addi r1, r1, 64
; CHECK-NEXT: ld r0, 16(r1)
; CHECK-NEXT: mtlr r0
; CHECK-NEXT: ld r30, -16(r1) # 8-byte Folded Reload
; CHECK-NEXT: ld r29, -24(r1) # 8-byte Folded Reload
; CHECK-NEXT: blr
; CHECK-NEXT: .LBB0_5: # %bb2
; CHECK-NEXT: .LBB0_6: # %bb14
bb:
br i1 undef, label %bb3, label %bb2
bb2: ; preds = %bb
unreachable
bb3: ; preds = %bb
%tmp = sub i64 %arg1, %arg
br i1 undef, label %bb4, label %bb14
bb4: ; preds = %bb3
br label %bb5
bb5: ; preds = %bb5, %bb4
%tmp6 = phi i64 [ %tmp12, %bb5 ], [ 0, %bb4 ]
%tmp7 = getelementptr inbounds float, float* null, i64 %tmp6
%tmp8 = load float, float* %tmp7, align 4
%tmp9 = fpext float %tmp8 to double
%tmp10 = tail call i64 @llvm.lrint.i64.f64(double %tmp9) #2
%tmp11 = trunc i64 %tmp10 to i8
store i8 %tmp11, i8* undef, align 1
%tmp12 = add nuw i64 %tmp6, 1
%tmp13 = icmp eq i64 %tmp12, %tmp
br i1 %tmp13, label %bb15, label %bb5
bb14: ; preds = %bb3
unreachable
bb15: ; preds = %bb5
ret void
}
declare i64 @llvm.lrint.i64.f64(double)