[PowerPC][NFC] Add test for comparison between two virtual registers

[Yi-Hong.Lyu]

Summary

Add test for https://reviews.llvm.org/D60506#inline-540291to show differences in code-gen.

llvm/test/CodeGen/PowerPC/use-cr-result-of-dom-icmp-st.ll

if.end:                                           ; preds = %entry
   %spec.select = mul nsw i32 %mul, %a
   br label %return
 
 return:                                           ; preds = %if.end, %entry
   %retval.0.in = phi i32 [ %b, %entry ], [ %spec.select, %if.end ]
   %retval.0 = sext i32 %retval.0.in to i64
   ret i64 %retval.0
 }
+
+; Please note the following functions are not generated from c code but
+; modified from tests above manually. However, the naming convention of
+; function name is the same.
+
+define i64 @ll_a_op_b_c(i64 %a, i64 %b, i64 %c) {
+; PPC64LE-LABEL: ll_a_op_b_c:
+; PPC64LE:       # %bb.0: # %entry
+; PPC64LE-NEXT:    sld 6, 3, 4
+; PPC64LE-NEXT:    cmpd 6, 5
+; PPC64LE-NEXT:    ble 0, .LBB20_2
+; PPC64LE-NEXT:  # %bb.1: # %return
+; PPC64LE-NEXT:    mr 3, 4
+; PPC64LE-NEXT:    blr
+; PPC64LE-NEXT:  .LBB20_2: # %if.end
+; PPC64LE-NEXT:    cmpld 6, 5
+; PPC64LE-NEXT:    li 5, 1
+; PPC64LE-NEXT:    isel 4, 4, 5, 2
+; PPC64LE-NEXT:    mulld 3, 4, 3
+; PPC64LE-NEXT:    blr
+entry:
+  %shl = shl i64 %a, %b
+  %cmp = icmp sgt i64 %shl, %c
+  br i1 %cmp, label %return, label %if.end
+
+if.end:                                           ; preds = %entry
+  %cmp2 = icmp eq i64 %shl, %c
+  %mul = select i1 %cmp2, i64 %b, i64 1
+  %spec.select = mul nsw i64 %mul, %a
+  ret i64 %spec.select
+
+return:                                           ; preds = %entry
+  ret i64 %b
+}
+
+define i64 @ll_a_c(i64 %a, i64 %b, i64 %c) {
+; PPC64LE-LABEL: ll_a_c:
+; PPC64LE:       # %bb.0: # %entry
+; PPC64LE-NEXT:    cmpd 3, 5
+; PPC64LE-NEXT:    ble 0, .LBB21_2
+; PPC64LE-NEXT:  # %bb.1: # %return
+; PPC64LE-NEXT:    mr 3, 4
+; PPC64LE-NEXT:    blr
+; PPC64LE-NEXT:  .LBB21_2: # %if.end
+; PPC64LE-NEXT:    cmpld 3, 5
+; PPC64LE-NEXT:    li 5, 1
+; PPC64LE-NEXT:    isel 4, 4, 5, 2
+; PPC64LE-NEXT:    mulld 3, 4, 3
+; PPC64LE-NEXT:    blr
+entry:
+  %cmp = icmp sgt i64 %a, %c
+  br i1 %cmp, label %return, label %if.end
+
+if.end:                                           ; preds = %entry
+  %cmp1 = icmp eq i64 %a, %c
+  %mul = select i1 %cmp1, i64 %b, i64 1
+  %spec.select = mul nsw i64 %mul, %a
+  ret i64 %spec.select
+
+return:                                           ; preds = %entry
+  ret i64 %b
+}
+
+define i64 @i_a_op_b_c(i32 signext %a, i32 signext %b, i32 signext %c) {
+; PPC64LE-LABEL: i_a_op_b_c:
+; PPC64LE:       # %bb.0: # %entry
+; PPC64LE-NEXT:    slw 7, 3, 4
+; PPC64LE-NEXT:    li 6, 1
+; PPC64LE-NEXT:    cmplw 7, 5
+; PPC64LE-NEXT:    isel 6, 4, 6, 2
+; PPC64LE-NEXT:    cmpw 0, 7, 5
+; PPC64LE-NEXT:    mullw 3, 6, 3
+; PPC64LE-NEXT:    isel 3, 4, 3, 1
+; PPC64LE-NEXT:    extsw 3, 3
+; PPC64LE-NEXT:    blr
+entry:
+  %shl = shl i32 %a, %b
+  %cmp = icmp sgt i32 %shl, %c
+  br i1 %cmp, label %return, label %if.end
+
+if.end:                                           ; preds = %entry
+  %cmp2 = icmp eq i32 %shl, %c
+  %mul = select i1 %cmp2, i32 %b, i32 1
+  %spec.select = mul nsw i32 %mul, %a
+  br label %return
+
+return:                                           ; preds = %if.end, %entry
+  %retval.0.in = phi i32 [ %b, %entry ], [ %spec.select, %if.end ]
+  %retval.0 = sext i32 %retval.0.in to i64
+  ret i64 %retval.0
+}
+
+define i64 @i_a_c(i32 signext %a, i32 signext %b, i32 signext %c) {
+; PPC64LE-LABEL: i_a_c:
+; PPC64LE:       # %bb.0: # %entry
+; PPC64LE-NEXT:    li 6, 1
+; PPC64LE-NEXT:    cmplw 3, 5
+; PPC64LE-NEXT:    isel 6, 4, 6, 2
+; PPC64LE-NEXT:    cmpw 0, 3, 5
+; PPC64LE-NEXT:    mullw 6, 6, 3
+; PPC64LE-NEXT:    isel 3, 4, 6, 1
+; PPC64LE-NEXT:    extsw 3, 3
+; PPC64LE-NEXT:    blr
+entry:
+  %cmp = icmp sgt i32 %a, %c
+  br i1 %cmp, label %return, label %if.end
+
+if.end:                                           ; preds = %entry
+  %cmp1 = icmp eq i32 %a, %c
+  %mul = select i1 %cmp1, i32 %b, i32 1
+  %spec.select = mul nsw i32 %mul, %a
+  br label %return
+
+return:                                           ; preds = %if.end, %entry
+  %retval.0.in = phi i32 [ %b, %entry ], [ %spec.select, %if.end ]
+  %retval.0 = sext i32 %retval.0.in to i64
+  ret i64 %retval.0
+}