[RISCV][NFC] Add more constant materialization tests

[luismarques]

Summary

This patch adds more constant materialization tests, focusing on cases where we could improve our materialization instruction sequences (particularly for RV64). Various of these cases will be improved upon in follow-up patches.

(The patch also adds some comments in tests which indicate the hexadecimal value of the respective decimal literals, since the larger literals are hard to mentally map to their hex value).

[lenary]

Nice work!

[luismarques]

Add one more test case.

llvm/test/CodeGen/RISCV/imm.ll

 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    lui a0, 16
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: pos_i32_hi20_only:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    lui a0, 16
 ; RV64I-NEXT:    ret
-  ret i32 65536
+  ret i32 65536 ; 0x10000
 }
 
 define signext i32 @neg_i32_hi20_only() nounwind {
 ; RV32I-LABEL: neg_i32_hi20_only:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    lui a0, 1048560
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: neg_i32_hi20_only:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    lui a0, 1048560
 ; RV64I-NEXT:    ret
-  ret i32 -65536
+  ret i32 -65536 ; -0x10000
 }
 
 define i64 @imm64_1() nounwind {
 ; RV32I-LABEL: imm64_1:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    lui a0, 524288
 ; RV32I-NEXT:    mv a1, zero
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_1:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi a0, zero, 1
 ; RV64I-NEXT:    slli a0, a0, 31
 ; RV64I-NEXT:    ret
-  ret i64 2147483648
+  ret i64 2147483648 ; 0x8000_0000
 }
 
 ; TODO: This and similar constants with all 0s in the upper bits and all 1s in
 ; the lower bits could be lowered to addi a0, zero, -1 followed by a logical
 ; right shift.
 define i64 @imm64_2() nounwind {
 ; RV32I-LABEL: imm64_2:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    addi a0, zero, -1
 ; RV32I-NEXT:    mv a1, zero
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_2:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi a0, zero, 1
 ; RV64I-NEXT:    slli a0, a0, 32
 ; RV64I-NEXT:    addi a0, a0, -1
 ; RV64I-NEXT:    ret
-  ret i64 4294967295
+  ret i64 4294967295 ; 0xFFFF_FFFF
 }
 
 define i64 @imm64_3() nounwind {
 ; RV32I-LABEL: imm64_3:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    addi a1, zero, 1
 ; RV32I-NEXT:    mv a0, zero
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_3:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi a0, zero, 1
 ; RV64I-NEXT:    slli a0, a0, 32
 ; RV64I-NEXT:    ret
-  ret i64 4294967296
+  ret i64 4294967296 ; 0x1_0000_0000
 }
 
 define i64 @imm64_4() nounwind {
 ; RV32I-LABEL: imm64_4:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    lui a1, 524288
 ; RV32I-NEXT:    mv a0, zero
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_4:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi a0, zero, -1
 ; RV64I-NEXT:    slli a0, a0, 63
 ; RV64I-NEXT:    ret
-  ret i64 9223372036854775808
+  ret i64 9223372036854775808 ; 0x8000_0000_0000_0000
 }
 
 define i64 @imm64_5() nounwind {
 ; RV32I-LABEL: imm64_5:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    lui a1, 524288
 ; RV32I-NEXT:    mv a0, zero
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_5:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi a0, zero, -1
 ; RV64I-NEXT:    slli a0, a0, 63
 ; RV64I-NEXT:    ret
-  ret i64 -9223372036854775808
+  ret i64 -9223372036854775808 ; 0x8000_0000_0000_0000
 }
 
 define i64 @imm64_6() nounwind {
 ; RV32I-LABEL: imm64_6:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    lui a0, 74565
 ; RV32I-NEXT:    addi a1, a0, 1656
 ; RV32I-NEXT:    mv a0, zero
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_6:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    lui a0, 9321
 ; RV64I-NEXT:    addiw a0, a0, -1329
 ; RV64I-NEXT:    slli a0, a0, 35
 ; RV64I-NEXT:    ret
-  ret i64 1311768464867721216
+  ret i64 1311768464867721216 ; 0x1234_5678_0000_0000
 }
 
 define i64 @imm64_7() nounwind {
 ; RV32I-LABEL: imm64_7:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    lui a0, 45056
 ; RV32I-NEXT:    addi a0, a0, 15
 ; RV32I-NEXT:    lui a1, 458752
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_7:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi a0, zero, 7
 ; RV64I-NEXT:    slli a0, a0, 36
 ; RV64I-NEXT:    addi a0, a0, 11
 ; RV64I-NEXT:    slli a0, a0, 24
 ; RV64I-NEXT:    addi a0, a0, 15
 ; RV64I-NEXT:    ret
-  ret i64 8070450532432478223
+  ret i64 8070450532432478223 ; 0x7000_0000_0B00_000F
 }
 
 ; TODO: it can be preferable to put constants that are expensive to materialise
 ; into the constant pool, especially for -Os.
 define i64 @imm64_8() nounwind {
 ; RV32I-LABEL: imm64_8:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    lui a0, 633806
 ; RV32I-NEXT:    addi a0, a0, -272
 ; RV32I-NEXT:    lui a1, 74565
 ; RV32I-NEXT:    addi a1, a1, 1656
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_8:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    lui a0, 583
 ; RV64I-NEXT:    addiw a0, a0, -1875
 ; RV64I-NEXT:    slli a0, a0, 14
 ; RV64I-NEXT:    addi a0, a0, -947
 ; RV64I-NEXT:    slli a0, a0, 12
 ; RV64I-NEXT:    addi a0, a0, 1511
 ; RV64I-NEXT:    slli a0, a0, 13
 ; RV64I-NEXT:    addi a0, a0, -272
 ; RV64I-NEXT:    ret
-  ret i64 1311768467463790320
+  ret i64 1311768467463790320 ; 0x1234_5678_9ABC_DEF0
 }
 
 define i64 @imm64_9() nounwind {
 ; RV32I-LABEL: imm64_9:
 ; RV32I:       # %bb.0:
 ; RV32I-NEXT:    addi a0, zero, -1
 ; RV32I-NEXT:    addi a1, zero, -1
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: imm64_9:
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi a0, zero, -1
 ; RV64I-NEXT:    ret
   ret i64 -1
 }
+
+; Various cases where extraneous ADDIs can be inserted where a (left shifted)
+; LUI suffices.
+
+define i64 @imm_left_shifted_lui_1() nounwind {
+; RV32I-LABEL: imm_left_shifted_lui_1:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 524290
+; RV32I-NEXT:    mv a1, zero
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_left_shifted_lui_1:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    lui a0, 64
+; RV64I-NEXT:    addiw a0, a0, 1
+; RV64I-NEXT:    slli a0, a0, 13
+; RV64I-NEXT:    ret
+  ret i64 2147491840 ; 0x8000_2000
+}
+
+define i64 @imm_left_shifted_lui_2() nounwind {
+; RV32I-LABEL: imm_left_shifted_lui_2:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 4
+; RV32I-NEXT:    addi a1, zero, 1
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_left_shifted_lui_2:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    lui a0, 64
+; RV64I-NEXT:    addiw a0, a0, 1
+; RV64I-NEXT:    slli a0, a0, 14
+; RV64I-NEXT:    ret
+  ret i64 4294983680 ; 0x1_0000_4000
+}
+
+define i64 @imm_left_shifted_lui_3() nounwind {
+; RV32I-LABEL: imm_left_shifted_lui_3:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a1, a0, 1
+; RV32I-NEXT:    mv a0, zero
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_left_shifted_lui_3:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addiw a0, a0, 1
+; RV64I-NEXT:    slli a0, a0, 32
+; RV64I-NEXT:    ret
+  ret i64 17596481011712 ; 0x1001_0000_0000
+}
+
+; Various cases where extraneous ADDIs can be inserted where a (right shifted)
+; LUI suffices, or where multiple ADDIs can be used instead of a single LUI.
+
+define i64 @imm_right_shifted_lui_1() nounwind {
+; RV32I-LABEL: imm_right_shifted_lui_1:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 1048575
+; RV32I-NEXT:    addi a0, a0, 1
+; RV32I-NEXT:    lui a1, 16
+; RV32I-NEXT:    addi a1, a1, -1
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_right_shifted_lui_1:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi a0, zero, 1
+; RV64I-NEXT:    slli a0, a0, 36
+; RV64I-NEXT:    addi a0, a0, -1
+; RV64I-NEXT:    slli a0, a0, 12
+; RV64I-NEXT:    addi a0, a0, 1
+; RV64I-NEXT:    ret
+  ret i64 281474976706561 ; 0xFFFF_FFFF_F001
+}
+
+define i64 @imm_right_shifted_lui_2() nounwind {
+; RV32I-LABEL: imm_right_shifted_lui_2:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 1048575
+; RV32I-NEXT:    addi a0, a0, 1
+; RV32I-NEXT:    addi a1, zero, 255
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_right_shifted_lui_2:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    lui a0, 65536
+; RV64I-NEXT:    addiw a0, a0, -1
+; RV64I-NEXT:    slli a0, a0, 12
+; RV64I-NEXT:    addi a0, a0, 1
+; RV64I-NEXT:    ret
+  ret i64 1099511623681 ; 0xFF_FFFF_F001
+}
+
+; We can materialize the upper bits with a single (shifted) LUI, but that option
+; can be missed due to the lower bits, which aren't just 1s or just 0s.
+
+define i64 @imm_decoupled_lui_addi() nounwind {
+; RV32I-LABEL: imm_decoupled_lui_addi:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi a0, zero, -3
+; RV32I-NEXT:    lui a1, 1
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_decoupled_lui_addi:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addiw a0, a0, 1
+; RV64I-NEXT:    slli a0, a0, 32
+; RV64I-NEXT:    addi a0, a0, -3
+; RV64I-NEXT:    ret
+  ret i64 17596481011709 ; 0x1000_FFFF_FFFD
+}
+
+; This constant can be materialized for RV64 with LUI+SRLI+XORI.
+
+define i64 @imm_end_xori_1() nounwind {
+; RV32I-LABEL: imm_end_xori_1:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 8192
+; RV32I-NEXT:    addi a0, a0, -1
+; RV32I-NEXT:    lui a1, 917504
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_end_xori_1:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi a0, zero, -1
+; RV64I-NEXT:    slli a0, a0, 36
+; RV64I-NEXT:    addi a0, a0, 1
+; RV64I-NEXT:    slli a0, a0, 25
+; RV64I-NEXT:    addi a0, a0, -1
+; RV64I-NEXT:    ret
+  ret i64 -2305843009180139521 ; 0xE000_0000_01FF_FFFF
+}
+
+; This constant can be materialized for RV64 with ADDI+SLLI+ADDI+ADDI.
+
+define i64 @imm_end_2addi_1() nounwind {
+; RV32I-LABEL: imm_end_2addi_1:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 1048575
+; RV32I-NEXT:    addi a0, a0, 2047
+; RV32I-NEXT:    lui a1, 1048512
+; RV32I-NEXT:    addi a1, a1, 127
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_end_2addi_1:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi a0, zero, -2047
+; RV64I-NEXT:    slli a0, a0, 27
+; RV64I-NEXT:    addi a0, a0, -1
+; RV64I-NEXT:    slli a0, a0, 12
+; RV64I-NEXT:    addi a0, a0, 2047
+; RV64I-NEXT:    ret
+  ret i64 -1125350151030785 ; 0xFFFC_007F_FFFF_F7FF
+}
+
+; This constant can be more efficiently materialized for RV64 if we use two
+; registers instead of one.
+
+define i64 @imm_2reg_1() nounwind {
+; RV32I-LABEL: imm_2reg_1:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 74565
+; RV32I-NEXT:    addi a0, a0, 1656
+; RV32I-NEXT:    lui a1, 983040
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: imm_2reg_1:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi a0, zero, -1
+; RV64I-NEXT:    slli a0, a0, 35
+; RV64I-NEXT:    addi a0, a0, 9
+; RV64I-NEXT:    slli a0, a0, 13
+; RV64I-NEXT:    addi a0, a0, 837
+; RV64I-NEXT:    slli a0, a0, 12
+; RV64I-NEXT:    addi a0, a0, 1656
+; RV64I-NEXT:    ret
+  ret i64 -1152921504301427080 ; 0xF000_0000_1234_5678
+}

llvm/test/MC/RISCV/rv64i-aliases-valid.s

 # CHECK-EXPAND: addi t4, t4, -947
 # CHECK-EXPAND: slli t4, t4, 12
 # CHECK-EXPAND: addi t4, t4, 1511
 # CHECK-EXPAND: slli t4, t4, 13
 # CHECK-EXPAND: addi t4, t4, -272
 li t4, 0x123456789abcdef0
 # CHECK-EXPAND: addi t5, zero, -1
 li t5, 0xFFFFFFFFFFFFFFFF
+# CHECK-EXPAND: lui t6, 64
+# CHECK-EXPAND: addiw t6, t6, 1
+# CHECK-EXPAND: slli t6, t6, 13
+li t6, 0x80002000
+# CHECK-EXPAND: lui t0, 64
+# CHECK-EXPAND: addiw t0, t0, 1
+# CHECK-EXPAND: slli t0, t0, 14
+li x5, 0x100004000
+# CHECK-EXPAND: lui t1, 1
+# CHECK-EXPAND: addiw t1, t1, 1
+# CHECK-EXPAND: slli t1, t1, 32
+li x6, 0x100100000000
+# CHECK-EXPAND: addi t2, zero, 1
+# CHECK-EXPAND: slli t2, t2, 36
+# CHECK-EXPAND: addi t2, t2, -1
+# CHECK-EXPAND: slli t2, t2, 12
+# CHECK-EXPAND: addi t2, t2, 1
+li x7, 0xFFFFFFFFF001
+# CHECK-EXPAND: lui s0, 65536
+# CHECK-EXPAND: addiw s0, s0, -1
+# CHECK-EXPAND: slli s0, s0, 12
+# CHECK-EXPAND: addi s0, s0, 1
+li x8, 0xFFFFFFF001
+# CHECK-EXPAND: lui s1, 1
+# CHECK-EXPAND: addiw s1, s1, 1
+# CHECK-EXPAND: slli s1, s1, 32
+# CHECK-EXPAND: addi s1, s1, -3
+li x9, 0x1000FFFFFFFD
+# CHECK-EXPAND: addi a0, zero, -1
+# CHECK-EXPAND: slli a0, a0, 36
+# CHECK-EXPAND: addi a0, a0, 1
+# CHECK-EXPAND: slli a0, a0, 25
+# CHECK-EXPAND: addi a0, a0, -1
+li x10, 0xE000000001FFFFFF
+# CHECK-EXPAND: addi a1, zero, -2047
+# CHECK-EXPAND: slli a1, a1, 27
+# CHECK-EXPAND: addi a1, a1, -1
+# CHECK-EXPAND: slli a1, a1, 12
+# CHECK-EXPAND: addi a1, a1, 2047
+li x11, 0xFFFC007FFFFFF7FF
 
 # CHECK-EXPAND: addi a0, zero, 1110
 li a0, %lo(0x123456)
 
 # CHECK-OBJ-NOALIAS: addi a0, zero, 0
 # CHECK-OBJ: R_RISCV_LO12
 li a0, %lo(foo)
 # CHECK-OBJ-NOALIAS: addi a0, zero, 0