Index: llvm/test/Transforms/SLPVectorizer/X86/powi-regression.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/SLPVectorizer/X86/powi-regression.ll
@@ -0,0 +1,61 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -mtriple=x86_64-linux-gnu -mcpu=x86-64-v2 -basic-aa -slp-vectorizer -S | FileCheck %s
+
+; FIXME: Ensure llvm.powi.* intrinsics are vectorized.
+
+define <2 x double> @PR53887_v2f64(<2 x double> noundef %x) {
+; CHECK-LABEL: @PR53887_v2f64(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[VECEXT:%.*]] = extractelement <2 x double> [[X:%.*]], i64 0
+; CHECK-NEXT:    [[TMP0:%.*]] = tail call fast double @llvm.powi.f64.i32(double [[VECEXT]], i32 6)
+; CHECK-NEXT:    [[VECINIT:%.*]] = insertelement <2 x double> undef, double [[TMP0]], i64 0
+; CHECK-NEXT:    [[VECEXT1:%.*]] = extractelement <2 x double> [[X]], i64 1
+; CHECK-NEXT:    [[TMP1:%.*]] = tail call fast double @llvm.powi.f64.i32(double [[VECEXT1]], i32 6)
+; CHECK-NEXT:    [[VECINIT3:%.*]] = insertelement <2 x double> [[VECINIT]], double [[TMP1]], i64 1
+; CHECK-NEXT:    ret <2 x double> [[VECINIT3]]
+;
+entry:
+  %vecext = extractelement <2 x double> %x, i64 0
+  %0 = tail call fast double @llvm.powi.f64.i32(double %vecext, i32 6)
+  %vecinit = insertelement <2 x double> undef, double %0, i64 0
+  %vecext1 = extractelement <2 x double> %x, i64 1
+  %1 = tail call fast double @llvm.powi.f64.i32(double %vecext1, i32 6)
+  %vecinit3 = insertelement <2 x double> %vecinit, double %1, i64 1
+  ret <2 x double> %vecinit3
+}
+
+define <4 x double> @PR53887_v4f64(<4 x double> noundef %x) local_unnamed_addr #0 {
+; CHECK-LABEL: @PR53887_v4f64(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[VECEXT:%.*]] = extractelement <4 x double> [[X:%.*]], i64 0
+; CHECK-NEXT:    [[VECEXT1:%.*]] = extractelement <4 x double> [[X]], i64 1
+; CHECK-NEXT:    [[TMP0:%.*]] = insertelement <2 x double> poison, double [[VECEXT]], i32 0
+; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <2 x double> [[TMP0]], double [[VECEXT1]], i32 1
+; CHECK-NEXT:    [[TMP2:%.*]] = call fast <2 x double> @llvm.powi.v2f64.i32(<2 x double> [[TMP1]], i32 6)
+; CHECK-NEXT:    [[TMP3:%.*]] = shufflevector <2 x double> [[TMP2]], <2 x double> poison, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
+; CHECK-NEXT:    [[VECEXT4:%.*]] = extractelement <4 x double> [[X]], i64 2
+; CHECK-NEXT:    [[VECEXT7:%.*]] = extractelement <4 x double> [[X]], i64 3
+; CHECK-NEXT:    [[TMP4:%.*]] = insertelement <2 x double> poison, double [[VECEXT4]], i32 0
+; CHECK-NEXT:    [[TMP5:%.*]] = insertelement <2 x double> [[TMP4]], double [[VECEXT7]], i32 1
+; CHECK-NEXT:    [[TMP6:%.*]] = call fast <2 x double> @llvm.powi.v2f64.i32(<2 x double> [[TMP5]], i32 6)
+; CHECK-NEXT:    [[TMP7:%.*]] = shufflevector <2 x double> [[TMP6]], <2 x double> poison, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
+; CHECK-NEXT:    [[VECINIT91:%.*]] = shufflevector <4 x double> [[TMP3]], <4 x double> [[TMP7]], <4 x i32> <i32 0, i32 1, i32 4, i32 5>
+; CHECK-NEXT:    ret <4 x double> [[VECINIT91]]
+;
+entry:
+  %vecext = extractelement <4 x double> %x, i64 0
+  %0 = tail call fast double @llvm.powi.f64.i32(double %vecext, i32 6) #2
+  %vecinit = insertelement <4 x double> undef, double %0, i64 0
+  %vecext1 = extractelement <4 x double> %x, i64 1
+  %1 = tail call fast double @llvm.powi.f64.i32(double %vecext1, i32 6) #2
+  %vecinit3 = insertelement <4 x double> %vecinit, double %1, i64 1
+  %vecext4 = extractelement <4 x double> %x, i64 2
+  %2 = tail call fast double @llvm.powi.f64.i32(double %vecext4, i32 6) #2
+  %vecinit6 = insertelement <4 x double> %vecinit3, double %2, i64 2
+  %vecext7 = extractelement <4 x double> %x, i64 3
+  %3 = tail call fast double @llvm.powi.f64.i32(double %vecext7, i32 6) #2
+  %vecinit9 = insertelement <4 x double> %vecinit6, double %3, i64 3
+  ret <4 x double> %vecinit9
+}
+
+declare double @llvm.powi.f64.i32(double, i32)