Add ISD::FROUND for libm round()

All libm floating-point rounding functions, except for round(), had their own
ISD nodes. Recent PowerPC cores have an instruction for round(), and so here I'm
adding ISD::FROUND so that round() can be custom lowered as well.

For the most part, this is straightforward. I've added an intrinsic
and a matching ISD node just like those for nearbyint() and friends. The
SelectionDAG pattern I've named frnd (because ISD::FP_ROUND has already claimed
fround).

This will be used by the PowerPC backend in a follow-up commit.

llvm-svn: 187926

1 files changed, 52 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/intrinsic.ll b/llvm/test/Transforms/LoopVectorize/intrinsic.ll
index 95b53b70ea8..566dcc75cd8 100644
--- a/llvm/test/Transforms/LoopVectorize/intrinsic.ll
+++ b/llvm/test/Transforms/LoopVectorize/intrinsic.ll
@@ -728,6 +728,58 @@ for.end:                                          ; preds = %for.body, %entry
 
 declare double @llvm.nearbyint.f64(double) nounwind readnone
 
+;CHECK-LABEL: @round_f32(
+;CHECK: llvm.round.v4f32
+;CHECK: ret void
+define void @round_f32(i32 %n, float* noalias %y, float* noalias %x) nounwind uwtable {
+entry:
+  %cmp6 = icmp sgt i32 %n, 0
+  br i1 %cmp6, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds float* %y, i64 %indvars.iv
+  %0 = load float* %arrayidx, align 4
+  %call = tail call float @llvm.round.f32(float %0) nounwind readnone
+  %arrayidx2 = getelementptr inbounds float* %x, i64 %indvars.iv
+  store float %call, float* %arrayidx2, align 4
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, %n
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+declare float @llvm.round.f32(float) nounwind readnone
+
+;CHECK-LABEL: @round_f64(
+;CHECK: llvm.round.v4f64
+;CHECK: ret void
+define void @round_f64(i32 %n, double* noalias %y, double* noalias %x) nounwind uwtable {
+entry:
+  %cmp6 = icmp sgt i32 %n, 0
+  br i1 %cmp6, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds double* %y, i64 %indvars.iv
+  %0 = load double* %arrayidx, align 8
+  %call = tail call double @llvm.round.f64(double %0) nounwind readnone
+  %arrayidx2 = getelementptr inbounds double* %x, i64 %indvars.iv
+  store double %call, double* %arrayidx2, align 8
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, %n
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+declare double @llvm.round.f64(double) nounwind readnone
+
 ;CHECK-LABEL: @fma_f32(
 ;CHECK: llvm.fma.v4f32
 ;CHECK: ret void