[InstCombine][NFC]: Add tests: foldSelectICmpAndAnd(): and is commuta…

…tive

Summary:
The fold added in D45108 did not account for the fact that
the and instruction is commutative, and if the mask is a variable,
the mask variable and the fold variable may be swapped.

I have noticed this by accident when looking into [[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]]

Reviewers: spatel, craig.topper

Reviewed By: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45538

llvm-svn: 329901

llvm/test/Transforms/InstCombine/select-of-bittest.ll

@@ -174,6 +174,24 @@ define i32 @f_var0(i32 %arg, i32 %arg1) {
   ret i32 %tmp5
 }
 
+; Should be exactly as the previous one
+define i32 @f_var0_commutative_and(i32 %arg, i32 %arg1) {
+; CHECK-LABEL: @f_var0_commutative_and(
+; CHECK-NEXT:    [[TMP:%.*]] = and i32 [[ARG1:%.*]], [[ARG:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i32 [[TMP]], 0
+; CHECK-NEXT:    [[TMP3:%.*]] = lshr i32 [[ARG]], 1
+; CHECK-NEXT:    [[TMP4:%.*]] = and i32 [[TMP3]], 1
+; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP2]], i32 [[TMP4]], i32 1
+; CHECK-NEXT:    ret i32 [[TMP5]]
+;
+  %tmp = and i32 %arg1, %arg ; in different order
+  %tmp2 = icmp eq i32 %tmp, 0
+  %tmp3 = lshr i32 %arg, 1
+  %tmp4 = and i32 %tmp3, 1
+  %tmp5 = select i1 %tmp2, i32 %tmp4, i32 1
+  ret i32 %tmp5
+}
+
 define <2 x i32> @f_var0_splatvec(<2 x i32> %arg, <2 x i32> %arg1) {
 ; CHECK-LABEL: @f_var0_splatvec(
 ; CHECK-NEXT:    [[TMP1:%.*]] = or <2 x i32> [[ARG1:%.*]], <i32 2, i32 2>
@@ -238,6 +256,22 @@ define i32 @f_var1(i32 %arg, i32 %arg1) {
   ret i32 %tmp4
 }
 
+; Should be exactly as the previous one
+define i32 @f_var1_commutative_and(i32 %arg, i32 %arg1) {
+; CHECK-LABEL: @f_var1_commutative_and(
+; CHECK-NEXT:    [[TMP:%.*]] = and i32 [[ARG1:%.*]], [[ARG:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i32 [[TMP]], 0
+; CHECK-NEXT:    [[TMP3:%.*]] = and i32 [[ARG]], 1
+; CHECK-NEXT:    [[TMP4:%.*]] = select i1 [[TMP2]], i32 [[TMP3]], i32 1
+; CHECK-NEXT:    ret i32 [[TMP4]]
+;
+  %tmp = and i32 %arg1, %arg ; in different order
+  %tmp2 = icmp eq i32 %tmp, 0
+  %tmp3 = and i32 %arg, 1
+  %tmp4 = select i1 %tmp2, i32 %tmp3, i32 1
+  ret i32 %tmp4
+}
+
 define <2 x i32> @f_var1_vec(<2 x i32> %arg, <2 x i32> %arg1) {
 ; CHECK-LABEL: @f_var1_vec(
 ; CHECK-NEXT:    [[TMP1:%.*]] = or <2 x i32> [[ARG1:%.*]], <i32 1, i32 1>
@@ -361,6 +395,24 @@ define i32 @f_var3(i32 %arg, i32 %arg1, i32 %arg2) {
   ret i32 %tmp6
 }
 
+; Should be exactly as the previous one
+define i32 @f_var3_commutative_and(i32 %arg, i32 %arg1, i32 %arg2) {
+; CHECK-LABEL: @f_var3_commutative_and(
+; CHECK-NEXT:    [[TMP:%.*]] = and i32 [[ARG1:%.*]], [[ARG:%.*]]
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i32 [[TMP]], 0
+; CHECK-NEXT:    [[TMP4:%.*]] = lshr i32 [[ARG]], [[ARG2:%.*]]
+; CHECK-NEXT:    [[TMP5:%.*]] = and i32 [[TMP4]], 1
+; CHECK-NEXT:    [[TMP6:%.*]] = select i1 [[TMP3]], i32 [[TMP5]], i32 1
+; CHECK-NEXT:    ret i32 [[TMP6]]
+;
+  %tmp = and i32 %arg1, %arg ; in different order
+  %tmp3 = icmp eq i32 %tmp, 0
+  %tmp4 = lshr i32 %arg, %arg2
+  %tmp5 = and i32 %tmp4, 1
+  %tmp6 = select i1 %tmp3, i32 %tmp5, i32 1
+  ret i32 %tmp6
+}
+
 define <2 x i32> @f_var3_splatvec(<2 x i32> %arg, <2 x i32> %arg1, <2 x i32> %arg2) {
 ; CHECK-LABEL: @f_var3_splatvec(
 ; CHECK-NEXT:    [[TMP1:%.*]] = shl <2 x i32> <i32 1, i32 1>, [[ARG2:%.*]]