[clang] [llvm] [PowerPC] Fix behavior of rldimi/rlwimi/rlwnm builtins (PR #85040)

[Chen Zheng via cfe-commits]

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@@ -72,4 +72,74 @@ define i64 @rldimi_intrinsic(i64 %a) {
   ret i64 %r3
 }
 
+define i64 @rldimi5(i64 %a, i64 %b) {
+; CHECK-LABEL: rldimi5:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    rldimi 4, 3, 8, 40
+; CHECK-NEXT:    mr 3, 4
+; CHECK-NEXT:    blr
+  %r = call i64 @llvm.ppc.rldimi(i64 %a, i64 %b, i32 8, i64 16776960) ; 0xffff << 8
+  ret i64 %r
+}
+
+define i64 @rldimi6(i64 %a, i64 %b) {
+; CHECK-LABEL: rldimi6:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    rotldi 3, 3, 1
+; CHECK-NEXT:    rldimi 4, 3, 7, 41
+; CHECK-NEXT:    mr 3, 4
+; CHECK-NEXT:    blr
+  %r = call i64 @llvm.ppc.rldimi(i64 %a, i64 %b, i32 8, i64 8388480) ; 0xffff << 7
+  ret i64 %r
+}
+
+define i64 @rldimi7(i64 %a, i64 %b) {
+; CHECK-LABEL: rldimi7:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    rotldi 3, 3, 63
+; CHECK-NEXT:    rldimi 4, 3, 9, 39
+; CHECK-NEXT:    mr 3, 4
+; CHECK-NEXT:    blr
+  %r = call i64 @llvm.ppc.rldimi(i64 %a, i64 %b, i32 8, i64 33553920) ; 0xffff << 9
+  ret i64 %r
+}
+
+define i64 @rldimi8(i64 %a, i64 %b) {
+; CHECK-LABEL: rldimi8:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    mr 3, 4
+; CHECK-NEXT:    blr
+  %r = call i64 @llvm.ppc.rldimi(i64 %a, i64 %b, i32 0, i64 0)
+  ret i64 %r
+}
+
+define i64 @rldimi9(i64 %a, i64 %b) {
+; CHECK-LABEL: rldimi9:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    mr 3, 4
+; CHECK-NEXT:    blr
+  %r = call i64 @llvm.ppc.rldimi(i64 %a, i64 %b, i32 63, i64 0)
+  ret i64 %r
+}
+
+define i64 @rldimi10(i64 %a, i64 %b) {
+; CHECK-LABEL: rldimi10:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    rldimi 4, 3, 0, 0
+; CHECK-NEXT:    mr 3, 4
+; CHECK-NEXT:    blr
+  %r = call i64 @llvm.ppc.rldimi(i64 %a, i64 %b, i32 0, i64 -1)
+  ret i64 %r
+}
+
+define i64 @rldimi11(i64 %a, i64 %b) {
+; CHECK-LABEL: rldimi11:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    rldimi 4, 3, 8, 56
+; CHECK-NEXT:    mr 3, 4
+; CHECK-NEXT:    blr
+  %r = call i64 @llvm.ppc.rldimi(i64 %a, i64 %b, i32 8, i64 -1)
----------------
chenzheng1030 wrote:

If we change to use `ISD::ROTL`, we will get `rotldi` as this place. Although `rldimi 4, 3, 8, 56` is right, it uses a wrap full mask. `rotldi` may be more friendly for optimizations like PPC peepholes.

https://github.com/llvm/llvm-project/pull/85040