[flang] update PPC vector tests (NFC) (llvm#126256)

Replace 'undef' with 'poison' based on commit f4e3b87

Author: kkwli

flang/test/Lower/PowerPC/ppc-vec-load-elem-order.f90

@@ -719,8 +719,8 @@ subroutine vec_xlds_testi64a(arg1, arg2, res)
 ! LLVMIR: %[[arg1:.*]] = load i64, ptr %0, align 8
 ! LLVMIR: %[[addr:.*]] = getelementptr i8, ptr %1, i64 %[[arg1]]
 ! LLVMIR: %[[ld:.*]] = load i64, ptr %[[addr]], align 8
-! LLVMIR: %[[insrt:.*]] = insertelement <2 x i64> undef, i64 %[[ld]], i32 0
-! LLVMIR: %[[shflv:.*]] = shufflevector <2 x i64> %[[insrt]], <2 x i64> undef, <2 x i32> zeroinitializer
+! LLVMIR: %[[insrt:.*]] = insertelement <2 x i64> poison, i64 %[[ld]], i32 0
+! LLVMIR: %[[shflv:.*]] = shufflevector <2 x i64> %[[insrt]], <2 x i64> poison, <2 x i32> zeroinitializer
 ! LLVMIR: store <2 x i64> %[[shflv]], ptr %2, align 16
 end subroutine vec_xlds_testi64a
 
@@ -734,8 +734,8 @@ subroutine vec_xlds_testf64a(arg1, arg2, res)
 ! LLVMIR: %[[arg1:.*]] = load i64, ptr %0, align 8
 ! LLVMIR: %[[addr:.*]] = getelementptr i8, ptr %1, i64 %[[arg1]]
 ! LLVMIR: %[[ld:.*]] = load i64, ptr %[[addr]], align 8
-! LLVMIR: %[[insrt:.*]] = insertelement <2 x i64> undef, i64 %[[ld]], i32 0
-! LLVMIR: %[[shflv:.*]] = shufflevector <2 x i64> %[[insrt]], <2 x i64> undef, <2 x i32> zeroinitializer
+! LLVMIR: %[[insrt:.*]] = insertelement <2 x i64> poison, i64 %[[ld]], i32 0
+! LLVMIR: %[[shflv:.*]] = shufflevector <2 x i64> %[[insrt]], <2 x i64> poison, <2 x i32> zeroinitializer
 ! LLVMIR: %[[bc:.*]] = bitcast <2 x i64> %[[shflv]] to <2 x double>
 ! LLVMIR: store <2 x double> %[[bc]], ptr %2, align 16
 end subroutine vec_xlds_testf64a

flang/test/Lower/PowerPC/ppc-vec-load.f90

@@ -683,8 +683,8 @@ subroutine vec_xlds_testi64a(arg1, arg2, res)
 ! LLVMIR: %[[arg1:.*]] = load i64, ptr %0, align 8
 ! LLVMIR: %[[addr:.*]] = getelementptr i8, ptr %1, i64 %[[arg1]]
 ! LLVMIR: %[[ld:.*]] = load i64, ptr %[[addr]], align 8
-! LLVMIR: %[[insrt:.*]] = insertelement <2 x i64> undef, i64 %[[ld]], i32 0
-! LLVMIR: %[[shfl:.*]] = shufflevector <2 x i64> %[[insrt]], <2 x i64> undef, <2 x i32> zeroinitializer
+! LLVMIR: %[[insrt:.*]] = insertelement <2 x i64> poison, i64 %[[ld]], i32 0
+! LLVMIR: %[[shfl:.*]] = shufflevector <2 x i64> %[[insrt]], <2 x i64> poison, <2 x i32> zeroinitializer
 ! LLVMIR: store <2 x i64> %[[shfl]], ptr %2, align 16
 end subroutine vec_xlds_testi64a
 
@@ -698,8 +698,8 @@ subroutine vec_xlds_testf64a(arg1, arg2, res)
 ! LLVMIR: %[[arg1:.*]] = load i64, ptr %0, align 8
 ! LLVMIR: %[[addr:.*]] = getelementptr i8, ptr %1, i64 %[[arg1]]
 ! LLVMIR: %[[ld:.*]] = load i64, ptr %[[addr]], align 8
-! LLVMIR: %[[insrt:.*]] = insertelement <2 x i64> undef, i64 %[[ld]], i32 0
-! LLVMIR: %[[shfl:.*]] = shufflevector <2 x i64> %[[insrt]], <2 x i64> undef, <2 x i32> zeroinitializer
+! LLVMIR: %[[insrt:.*]] = insertelement <2 x i64> poison, i64 %[[ld]], i32 0
+! LLVMIR: %[[shfl:.*]] = shufflevector <2 x i64> %[[insrt]], <2 x i64> poison, <2 x i32> zeroinitializer
 ! LLVMIR: %[[bc:.*]] = bitcast <2 x i64> %[[shfl]] to <2 x double>
 ! LLVMIR: store <2 x double> %[[bc]], ptr %2, align 16
 end subroutine vec_xlds_testf64a

flang/test/Lower/PowerPC/ppc-vec-splat-elem-order.f90

@@ -8,8 +8,8 @@ subroutine vec_splat_testf32i64(x)
 
 ! LLVMIR: %[[x:.*]] = load <4 x float>, ptr %{{[0-9]}}, align 16
 ! LLVMIR: %[[ele:.*]] = extractelement <4 x float> %[[x]], i64 3
-! LLVMIR: %[[ins:.*]] = insertelement <4 x float> undef, float %[[ele]], i32 0
-! LLVMIR: %[[y:.*]] = shufflevector <4 x float> %[[ins]], <4 x float> undef, <4 x i32> zeroinitializer
+! LLVMIR: %[[ins:.*]] = insertelement <4 x float> poison, float %[[ele]], i32 0
+! LLVMIR: %[[y:.*]] = shufflevector <4 x float> %[[ins]], <4 x float> poison, <4 x i32> zeroinitializer
 ! LLVMIR: store <4 x float> %[[y]], ptr %{{[0-9]}}, align 16
 end subroutine vec_splat_testf32i64
 
@@ -20,7 +20,7 @@ subroutine vec_splat_testu8i16(x)
 
 ! LLVMIR: %[[x:.*]] = load <16 x i8>, ptr %{{[0-9]}}, align 16
 ! LLVMIR: %[[ele:.*]] = extractelement <16 x i8> %[[x]], i16 15
-! LLVMIR: %[[ins:.*]] = insertelement <16 x i8> undef, i8 %[[ele]], i32 0
-! LLVMIR: %[[y:.*]] = shufflevector <16 x i8> %[[ins]], <16 x i8> undef, <16 x i32> zeroinitializer
+! LLVMIR: %[[ins:.*]] = insertelement <16 x i8> poison, i8 %[[ele]], i32 0
+! LLVMIR: %[[y:.*]] = shufflevector <16 x i8> %[[ins]], <16 x i8> poison, <16 x i32> zeroinitializer
 ! LLVMIR: store <16 x i8> %[[y]], ptr %{{[0-9]}}, align 16
 end subroutine vec_splat_testu8i16