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[RISCV] Add special case to constant materialization to remove trailing zeros first. 

If there are fewer than 12 trailing zeros, we'll try to use an ADDI
at the end of the sequence. If we strip trailing zeros and end the
sequence with a SLLI we might find a shorter sequence.

Differential Revision: https://reviews.llvm.org/D124148
This commit is contained in:
Craig Topper 2022-04-20 23:09:59 -07:00
parent ac94073daa
commit 98b866892d
8 changed files with 89 additions and 113 deletions
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18
llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp
View File

@ -162,6 +162,24 @@ InstSeq generateInstSeq(int64_t Val, const FeatureBitset &ActiveFeatures) {
RISCVMatInt::InstSeq Res;
generateInstSeqImpl(Val, ActiveFeatures, Res);
// If there are trailing zeros, try generating a sign extended constant with
// no trailing zeros and use a final SLLI to restore them.
if ((Val & 1) == 0 && Res.size() > 2) {
unsigned TrailingZeros = countTrailingZeros((uint64_t)Val);
int64_t ShiftedVal = Val >> TrailingZeros;
RISCVMatInt::InstSeq TmpSeq;
generateInstSeqImpl(ShiftedVal, ActiveFeatures, TmpSeq);
TmpSeq.push_back(RISCVMatInt::Inst(RISCV::SLLI, TrailingZeros));
// Keep the new sequence if it is an improvement.
if (TmpSeq.size() < Res.size()) {
Res = TmpSeq;
// A 2 instruction sequence is the best we can do.
if (Res.size() <= 2)
return Res;
}
}
// If the constant is positive we might be able to generate a shifted constant
// with no leading zeros and use a final SRLI to restore them.
if (Val > 0 && Res.size() > 2) {

92
llvm/test/CodeGen/RISCV/imm.ll
View File

@ -601,14 +601,13 @@ define i64 @imm64_8() nounwind {
;
; RV64IZBA-LABEL: imm64_8:
; RV64IZBA: # %bb.0:
; RV64IZBA-NEXT: lui a0, 583
; RV64IZBA-NEXT: addiw a0, a0, -1875
; RV64IZBA-NEXT: slli a0, a0, 14
; RV64IZBA-NEXT: addi a0, a0, -947
; RV64IZBA-NEXT: lui a0, 596523
; RV64IZBA-NEXT: addiw a0, a0, 965
; RV64IZBA-NEXT: slli.uw a0, a0, 13
; RV64IZBA-NEXT: addi a0, a0, -1347
; RV64IZBA-NEXT: slli a0, a0, 12
; RV64IZBA-NEXT: addi a0, a0, 1511
; RV64IZBA-NEXT: slli a0, a0, 13
; RV64IZBA-NEXT: addi a0, a0, -272
; RV64IZBA-NEXT: addi a0, a0, -529
; RV64IZBA-NEXT: slli a0, a0, 4
; RV64IZBA-NEXT: ret
;
; RV64IZBB-LABEL: imm64_8:
@ -1723,32 +1722,30 @@ define i64 @imm_2863311530() {
;
; RV64I-LABEL: imm_2863311530:
; RV64I: # %bb.0:
; RV64I-NEXT: lui a0, 171
; RV64I-NEXT: addiw a0, a0, -1365
; RV64I-NEXT: slli a0, a0, 12
; RV64I-NEXT: addi a0, a0, -1366
; RV64I-NEXT: lui a0, 349525
; RV64I-NEXT: addiw a0, a0, 1365
; RV64I-NEXT: slli a0, a0, 1
; RV64I-NEXT: ret
;
; RV64IZBA-LABEL: imm_2863311530:
; RV64IZBA: # %bb.0:
; RV64IZBA-NEXT: lui a0, 699051
; RV64IZBA-NEXT: addiw a0, a0, -1366
; RV64IZBA-NEXT: zext.w a0, a0
; RV64IZBA-NEXT: lui a0, 349525
; RV64IZBA-NEXT: addiw a0, a0, 1365
; RV64IZBA-NEXT: slli a0, a0, 1
; RV64IZBA-NEXT: ret
;
; RV64IZBB-LABEL: imm_2863311530:
; RV64IZBB: # %bb.0:
; RV64IZBB-NEXT: lui a0, 171
; RV64IZBB-NEXT: addiw a0, a0, -1365
; RV64IZBB-NEXT: slli a0, a0, 12
; RV64IZBB-NEXT: addi a0, a0, -1366
; RV64IZBB-NEXT: lui a0, 349525
; RV64IZBB-NEXT: addiw a0, a0, 1365
; RV64IZBB-NEXT: slli a0, a0, 1
; RV64IZBB-NEXT: ret
;
; RV64IZBS-LABEL: imm_2863311530:
; RV64IZBS: # %bb.0:
; RV64IZBS-NEXT: lui a0, 174763
; RV64IZBS-NEXT: addiw a0, a0, -1366
; RV64IZBS-NEXT: bseti a0, a0, 31
; RV64IZBS-NEXT: lui a0, 349525
; RV64IZBS-NEXT: addiw a0, a0, 1365
; RV64IZBS-NEXT: slli a0, a0, 1
; RV64IZBS-NEXT: ret
ret i64 2863311530 ; #0xaaaaaaaa
}
@ -1763,32 +1760,30 @@ define i64 @imm_neg_2863311530() {
;
; RV64I-LABEL: imm_neg_2863311530:
; RV64I: # %bb.0:
; RV64I-NEXT: lui a0, 1048405
; RV64I-NEXT: addiw a0, a0, 1365
; RV64I-NEXT: slli a0, a0, 12
; RV64I-NEXT: addi a0, a0, 1366
; RV64I-NEXT: lui a0, 699051
; RV64I-NEXT: addiw a0, a0, -1365
; RV64I-NEXT: slli a0, a0, 1
; RV64I-NEXT: ret
;
; RV64IZBA-LABEL: imm_neg_2863311530:
; RV64IZBA: # %bb.0:
; RV64IZBA-NEXT: lui a0, 908766
; RV64IZBA-NEXT: addiw a0, a0, -546
; RV64IZBA-NEXT: sh2add a0, a0, a0
; RV64IZBA-NEXT: lui a0, 699051
; RV64IZBA-NEXT: addiw a0, a0, -1365
; RV64IZBA-NEXT: slli a0, a0, 1
; RV64IZBA-NEXT: ret
;
; RV64IZBB-LABEL: imm_neg_2863311530:
; RV64IZBB: # %bb.0:
; RV64IZBB-NEXT: lui a0, 1048405
; RV64IZBB-NEXT: addiw a0, a0, 1365
; RV64IZBB-NEXT: slli a0, a0, 12
; RV64IZBB-NEXT: addi a0, a0, 1366
; RV64IZBB-NEXT: lui a0, 699051
; RV64IZBB-NEXT: addiw a0, a0, -1365
; RV64IZBB-NEXT: slli a0, a0, 1
; RV64IZBB-NEXT: ret
;
; RV64IZBS-LABEL: imm_neg_2863311530:
; RV64IZBS: # %bb.0:
; RV64IZBS-NEXT: lui a0, 873813
; RV64IZBS-NEXT: addiw a0, a0, 1366
; RV64IZBS-NEXT: bclri a0, a0, 31
; RV64IZBS-NEXT: lui a0, 699051
; RV64IZBS-NEXT: addiw a0, a0, -1365
; RV64IZBS-NEXT: slli a0, a0, 1
; RV64IZBS-NEXT: ret
ret i64 -2863311530 ; #0xffffffff55555556
}
@ -2002,12 +1997,11 @@ define i64 @imm_12900918536874() {
;
; RV64I-LABEL: imm_12900918536874:
; RV64I: # %bb.0:
; RV64I-NEXT: lui a0, 188
; RV64I-NEXT: addiw a0, a0, -1093
; RV64I-NEXT: lui a0, 384477
; RV64I-NEXT: addiw a0, a0, 1365
; RV64I-NEXT: slli a0, a0, 12
; RV64I-NEXT: addi a0, a0, -1365
; RV64I-NEXT: slli a0, a0, 12
; RV64I-NEXT: addi a0, a0, -1366
; RV64I-NEXT: addi a0, a0, 1365
; RV64I-NEXT: slli a0, a0, 1
; RV64I-NEXT: ret
;
; RV64IZBA-LABEL: imm_12900918536874:
@ -2020,22 +2014,20 @@ define i64 @imm_12900918536874() {
;
; RV64IZBB-LABEL: imm_12900918536874:
; RV64IZBB: # %bb.0:
; RV64IZBB-NEXT: lui a0, 188
; RV64IZBB-NEXT: addiw a0, a0, -1093
; RV64IZBB-NEXT: lui a0, 384477
; RV64IZBB-NEXT: addiw a0, a0, 1365
; RV64IZBB-NEXT: slli a0, a0, 12
; RV64IZBB-NEXT: addi a0, a0, -1365
; RV64IZBB-NEXT: slli a0, a0, 12
; RV64IZBB-NEXT: addi a0, a0, -1366
; RV64IZBB-NEXT: addi a0, a0, 1365
; RV64IZBB-NEXT: slli a0, a0, 1
; RV64IZBB-NEXT: ret
;
; RV64IZBS-LABEL: imm_12900918536874:
; RV64IZBS: # %bb.0:
; RV64IZBS-NEXT: lui a0, 188
; RV64IZBS-NEXT: addiw a0, a0, -1093
; RV64IZBS-NEXT: lui a0, 384477
; RV64IZBS-NEXT: addiw a0, a0, 1365
; RV64IZBS-NEXT: slli a0, a0, 12
; RV64IZBS-NEXT: addi a0, a0, -1365
; RV64IZBS-NEXT: slli a0, a0, 12
; RV64IZBS-NEXT: addi a0, a0, -1366
; RV64IZBS-NEXT: addi a0, a0, 1365
; RV64IZBS-NEXT: slli a0, a0, 1
; RV64IZBS-NEXT: ret
ret i64 12900918536874
}

18
llvm/test/CodeGen/RISCV/rv64zba.ll
View File

@ -717,24 +717,6 @@ define i64 @imm_zextw() nounwind {
ret i64 4294967294 ; -2 in 32 bits.
}
define i64 @imm_zextw2() nounwind {
; RV64I-LABEL: imm_zextw2:
; RV64I: # %bb.0:
; RV64I-NEXT: lui a0, 171
; RV64I-NEXT: addiw a0, a0, -1365
; RV64I-NEXT: slli a0, a0, 12
; RV64I-NEXT: addi a0, a0, -1366
; RV64I-NEXT: ret
;
; RV64ZBA-LABEL: imm_zextw2:
; RV64ZBA: # %bb.0:
; RV64ZBA-NEXT: lui a0, 699051
; RV64ZBA-NEXT: addiw a0, a0, -1366
; RV64ZBA-NEXT: zext.w a0, a0
; RV64ZBA-NEXT: ret
ret i64 2863311530 ; 0xAAAAAAAA
}
define i64 @mul11(i64 %a) {
; RV64I-LABEL: mul11:
; RV64I: # %bb.0:

20
llvm/test/CodeGen/RISCV/rv64zbp.ll
View File

@ -1635,14 +1635,11 @@ define zeroext i32 @grev7_i32_zext(i32 zeroext %a) nounwind {
; RV64I-NEXT: and a0, a0, a2
; RV64I-NEXT: or a0, a1, a0
; RV64I-NEXT: slli a1, a0, 4
; RV64I-NEXT: lui a2, 241
; RV64I-NEXT: addiw a2, a2, -241
; RV64I-NEXT: slli a2, a2, 12
; RV64I-NEXT: addi a2, a2, 240
; RV64I-NEXT: and a1, a1, a2
; RV64I-NEXT: srli a0, a0, 4
; RV64I-NEXT: lui a2, 61681
; RV64I-NEXT: addiw a2, a2, -241
; RV64I-NEXT: slli a3, a2, 4
; RV64I-NEXT: and a1, a1, a3
; RV64I-NEXT: srli a0, a0, 4
; RV64I-NEXT: and a0, a0, a2
; RV64I-NEXT: or a0, a1, a0
; RV64I-NEXT: ret
@ -3195,15 +3192,12 @@ define i64 @shfl8_i64(i64 %a, i64 %b) nounwind {
; RV64I-NEXT: and a1, a0, a1
; RV64I-NEXT: slli a2, a0, 8
; RV64I-NEXT: li a3, 255
; RV64I-NEXT: slli a4, a3, 32
; RV64I-NEXT: addi a4, a4, 255
; RV64I-NEXT: slli a4, a4, 16
; RV64I-NEXT: slli a3, a3, 32
; RV64I-NEXT: addi a3, a3, 255
; RV64I-NEXT: slli a4, a3, 16
; RV64I-NEXT: and a2, a2, a4
; RV64I-NEXT: srli a0, a0, 8
; RV64I-NEXT: slli a3, a3, 24
; RV64I-NEXT: addi a3, a3, 1
; RV64I-NEXT: slli a3, a3, 16
; RV64I-NEXT: addi a3, a3, -256
; RV64I-NEXT: slli a3, a3, 8
; RV64I-NEXT: and a0, a0, a3
; RV64I-NEXT: or a0, a0, a1
; RV64I-NEXT: or a0, a2, a0

14
llvm/test/CodeGen/RISCV/vararg.ll
View File

@ -1540,10 +1540,9 @@ define void @va5_aligned_stack_caller() nounwind {
; LP64-LP64F-LP64D-FPELIM-NEXT: ld a2, %lo(.LCPI11_1)(a0)
; LP64-LP64F-LP64D-FPELIM-NEXT: lui a0, %hi(.LCPI11_2)
; LP64-LP64F-LP64D-FPELIM-NEXT: ld a3, %lo(.LCPI11_2)(a0)
; LP64-LP64F-LP64D-FPELIM-NEXT: lui a0, 1192
; LP64-LP64F-LP64D-FPELIM-NEXT: addiw a0, a0, 381
; LP64-LP64F-LP64D-FPELIM-NEXT: slli a0, a0, 12
; LP64-LP64F-LP64D-FPELIM-NEXT: addi a6, a0, -2048
; LP64-LP64F-LP64D-FPELIM-NEXT: lui a0, 2384
; LP64-LP64F-LP64D-FPELIM-NEXT: addiw a0, a0, 761
; LP64-LP64F-LP64D-FPELIM-NEXT: slli a6, a0, 11
; LP64-LP64F-LP64D-FPELIM-NEXT: li a0, 1
; LP64-LP64F-LP64D-FPELIM-NEXT: li a1, 11
; LP64-LP64F-LP64D-FPELIM-NEXT: li a4, 12
@ -1573,10 +1572,9 @@ define void @va5_aligned_stack_caller() nounwind {
; LP64-LP64F-LP64D-WITHFP-NEXT: ld a2, %lo(.LCPI11_1)(a0)
; LP64-LP64F-LP64D-WITHFP-NEXT: lui a0, %hi(.LCPI11_2)
; LP64-LP64F-LP64D-WITHFP-NEXT: ld a3, %lo(.LCPI11_2)(a0)
; LP64-LP64F-LP64D-WITHFP-NEXT: lui a0, 1192
; LP64-LP64F-LP64D-WITHFP-NEXT: addiw a0, a0, 381
; LP64-LP64F-LP64D-WITHFP-NEXT: slli a0, a0, 12
; LP64-LP64F-LP64D-WITHFP-NEXT: addi a6, a0, -2048
; LP64-LP64F-LP64D-WITHFP-NEXT: lui a0, 2384
; LP64-LP64F-LP64D-WITHFP-NEXT: addiw a0, a0, 761
; LP64-LP64F-LP64D-WITHFP-NEXT: slli a6, a0, 11
; LP64-LP64F-LP64D-WITHFP-NEXT: li a0, 1
; LP64-LP64F-LP64D-WITHFP-NEXT: li a1, 11
; LP64-LP64F-LP64D-WITHFP-NEXT: li a4, 12

16
llvm/test/MC/RISCV/rv64i-aliases-valid.s
View File

@ -170,6 +170,22 @@ li x10, 0xE000000001FFFFFF
# CHECK-ALIAS-NEXT: addi a1, a1, 2047
li x11, 0xFFFC007FFFFFF7FF
# CHECK-INST: lui a2, 349525
# CHECK-INST-NEXT: addiw a2, a2, 1365
# CHECK-INST-NEXT: slli a2, a2, 1
# CHECK-ALIAS: lui a2, 349525
# CHECK-ALIAS-NEXT: addiw a2, a2, 1365
# CHECK-ALIAS-NEXT: slli a2, a2, 1
li x12, 0xaaaaaaaa
# CHECK-INST: lui a3, 699051
# CHECK-INST-NEXT: addiw a3, a3, -1365
# CHECK-INST-NEXT: slli a3, a3, 1
# CHECK-ALIAS: lui a3, 699051
# CHECK-ALIAS-NEXT: addiw a3, a3, -1365
# CHECK-ALIAS-NEXT: slli a3, a3, 1
li x13, 0xffffffff55555556
# CHECK-INST: addi a0, zero, 1110
# CHECK-ALIAS: li a0, 1110
li a0, %lo(0x123456)

8
llvm/test/MC/RISCV/rv64zba-aliases-valid.s
View File

@ -25,14 +25,6 @@ zext.w x5, x6
# CHECK-S-OBJ-NEXT: zext.w t1, t1
li x6, 0xfffffffe
# CHECK-S-OBJ-NOALIAS: lui t2, 699051
# CHECK-S-OBJ-NOALIAS-NEXT: addiw t2, t2, -1366
# CHECK-S-OBJ-NOALIAS-NEXT: add.uw t2, t2, zero
# CHECK-S-OBJ: lui t2, 699051
# CHECK-S-OBJ-NEXT: addiw t2, t2, -1366
# CHECK-S-OBJ-NEXT: zext.w t2, t2
li x7, 0xaaaaaaaa
# CHECK-S-OBJ-NOALIAS: lui t0, 768955
# CHECK-S-OBJ-NOALIAS-NEXT: slli.uw t0, t0, 12
# CHECK-S-OBJ-NOALIAS-NEXT: addi t0, t0, 1979

16
llvm/test/MC/RISCV/rv64zbs-aliases-valid.s
View File

@ -31,22 +31,6 @@ binv x5, x6, 8
# CHECK-S-OBJ: bexti t0, t1, 8
bext x5, x6, 8
# CHECK-S-OBJ-NOALIAS: lui t0, 174763
# CHECK-S-OBJ-NOALIAS-NEXT: addiw t0, t0, -1366
# CHECK-S-OBJ-NOALIAS-NEXT: bseti t0, t0, 31
# CHECK-S-OBJ: lui t0, 174763
# CHECK-S-OBJ-NEXT: addiw t0, t0, -1366
# CHECK-S-OBJ-NEXT: bseti t0, t0, 31
li x5, 2863311530 # 0xaaaaaaaa
# CHECK-S-OBJ-NOALIAS: lui t0, 873813
# CHECK-S-OBJ-NOALIAS-NEXT: addiw t0, t0, 1366
# CHECK-S-OBJ-NOALIAS-NEXT: bclri t0, t0, 31
# CHECK-S-OBJ: lui t0, 873813
# CHECK-S-OBJ-NEXT: addiw t0, t0, 1366
# CHECK-S-OBJ-NEXT: bclri t0, t0, 31
li x5, -2863311530 # 0xffffffff55555556
# CHECK-S-OBJ-NOALIAS: addi t0, zero, 1365
# CHECK-S-OBJ-NOALIAS-NEXT: bseti t0, t0, 31
# CHECK-S-OBJ: li t0, 1365