[Analysis] isTriviallyVectorizable add vectorization for atan2 intrinsic

This change is part of this proposal: https://discourse.llvm.org/t/rfc-all-the-math-intrinsics/78294

This returns true from isTriviallyVectorizable for llvm.atan2 intrinsic.
It also adds llvm atan2 intrinsic equivalents to VecFuncs.def for massv.

Part of: Implement the atan2 HLSL Function #70096.

Author: tex3d

llvm/include/llvm/Analysis/VecFuncs.def

@@ -289,7 +289,9 @@ TLI_DEFINE_VECFUNC("acosf", "__acosf4", FIXED(4), "_ZGV_LLVM_N4v")
 TLI_DEFINE_VECFUNC("atan", "__atand2", FIXED(2), "_ZGV_LLVM_N2v")
 TLI_DEFINE_VECFUNC("atanf", "__atanf4", FIXED(4), "_ZGV_LLVM_N4v")
 TLI_DEFINE_VECFUNC("atan2", "__atan2d2", FIXED(2), "_ZGV_LLVM_N2vv")
+TLI_DEFINE_VECFUNC("llvm.atan2.f64", "__atan2d2", FIXED(2), "_ZGV_LLVM_N2vv")
 TLI_DEFINE_VECFUNC("atan2f", "__atan2f4", FIXED(4), "_ZGV_LLVM_N4vv")
+TLI_DEFINE_VECFUNC("llvm.atan2.f32", "__atan2f4", FIXED(4), "_ZGV_LLVM_N4vv")
 
 // Hyperbolic Functions
 TLI_DEFINE_VECFUNC("sinh", "__sinhd2", FIXED(2), "_ZGV_LLVM_N2v")

llvm/lib/Analysis/VectorUtils.cpp

@@ -69,6 +69,7 @@ bool llvm::isTriviallyVectorizable(Intrinsic::ID ID) {
   case Intrinsic::asin:
   case Intrinsic::acos:
   case Intrinsic::atan:
+  case Intrinsic::atan2:
   case Intrinsic::sin:
   case Intrinsic::cos:
   case Intrinsic::tan:

llvm/test/Transforms/LoopVectorize/PowerPC/massv-calls.ll

@@ -1244,6 +1244,52 @@ for.end:
   ret void
 }
 
+define void @atan2_f64_intrinsic(ptr nocapture %varray) {
+; CHECK-LABEL: @atan2_f64_intrinsic(
+; CHECK: __atan2d2{{.*}}<2 x double>
+; CHECK: ret void
+;
+entry:
+  br label %for.body
+
+for.body:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
+  %tmp = trunc i64 %iv to i32
+  %conv = sitofp i32 %tmp to double
+  %call = tail call double @llvm.atan2.f64(double %conv, double %conv)
+  %arrayidx = getelementptr inbounds double, ptr %varray, i64 %iv
+  store double %call, ptr %arrayidx, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond = icmp eq i64 %iv.next, 1000
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+define void @atan2_f32_intrinsic(ptr nocapture %varray) {
+; CHECK-LABEL: @atan2_f32_intrinsic(
+; CHECK: __atan2f4{{.*}}<4 x float>
+; CHECK: ret void
+;
+entry:
+  br label %for.body
+
+for.body:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
+  %tmp = trunc i64 %iv to i32
+  %conv = sitofp i32 %tmp to float
+  %call = tail call float @llvm.atan2.f32(float %conv, float %conv)
+  %arrayidx = getelementptr inbounds float, ptr %varray, i64 %iv
+  store float %call, ptr %arrayidx, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond = icmp eq i64 %iv.next, 1000
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
 define void @sinh_f64(ptr nocapture %varray) {
 ; CHECK-LABEL: @sinh_f64(
 ; CHECK: __sinhd2{{.*}}<2 x double>