[llvm] [SDAG] Use shifts if ISD::MUL is illegal when lowering ISD::CTPOP (PR #86505)

[Wang Pengcheng via llvm-commits]

================
@@ -10,29 +10,30 @@ body:             |
 
     ; MIPS32-LABEL: name: ctpop_i32
     ; MIPS32: liveins: $a0
-    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
-    ; MIPS32: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
-    ; MIPS32: [[LSHR:%[0-9]+]]:_(s32) = G_LSHR [[COPY]], [[C]](s32)
-    ; MIPS32: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 1431655765
-    ; MIPS32: [[AND:%[0-9]+]]:_(s32) = G_AND [[LSHR]], [[C1]]
-    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY]], [[AND]]
-    ; MIPS32: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 2
-    ; MIPS32: [[LSHR1:%[0-9]+]]:_(s32) = G_LSHR [[SUB]], [[C2]](s32)
-    ; MIPS32: [[C3:%[0-9]+]]:_(s32) = G_CONSTANT i32 858993459
-    ; MIPS32: [[AND1:%[0-9]+]]:_(s32) = G_AND [[LSHR1]], [[C3]]
-    ; MIPS32: [[AND2:%[0-9]+]]:_(s32) = G_AND [[SUB]], [[C3]]
-    ; MIPS32: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[AND1]], [[AND2]]
-    ; MIPS32: [[C4:%[0-9]+]]:_(s32) = G_CONSTANT i32 4
-    ; MIPS32: [[LSHR2:%[0-9]+]]:_(s32) = G_LSHR [[ADD]], [[C4]](s32)
-    ; MIPS32: [[ADD1:%[0-9]+]]:_(s32) = G_ADD [[LSHR2]], [[ADD]]
-    ; MIPS32: [[C5:%[0-9]+]]:_(s32) = G_CONSTANT i32 252645135
-    ; MIPS32: [[AND3:%[0-9]+]]:_(s32) = G_AND [[ADD1]], [[C5]]
-    ; MIPS32: [[C6:%[0-9]+]]:_(s32) = G_CONSTANT i32 16843009
-    ; MIPS32: [[MUL:%[0-9]+]]:_(s32) = G_MUL [[AND3]], [[C6]]
-    ; MIPS32: [[C7:%[0-9]+]]:_(s32) = G_CONSTANT i32 24
-    ; MIPS32: [[LSHR3:%[0-9]+]]:_(s32) = G_LSHR [[MUL]], [[C7]](s32)
-    ; MIPS32: $v0 = COPY [[LSHR3]](s32)
-    ; MIPS32: RetRA implicit $v0
+    ; MIPS32-NEXT: {{  $}}
----------------
wangpc-pp wrote:

Done.

https://github.com/llvm/llvm-project/pull/86505