[llvm] de0bcd0 - [RISCV] Use QC_E_ADDI while eliminating the frameindex (#139515)

via llvm-commits llvm-commits at lists.llvm.org
Thu May 15 17:17:07 PDT 2025


Author: Sudharsan Veeravalli
Date: 2025-05-16T05:47:04+05:30
New Revision: de0bcd0564e4e67ae2afe1bad41c7bc505362e19

URL: https://github.com/llvm/llvm-project/commit/de0bcd0564e4e67ae2afe1bad41c7bc505362e19
DIFF: https://github.com/llvm/llvm-project/commit/de0bcd0564e4e67ae2afe1bad41c7bc505362e19.diff

LOG: [RISCV] Use QC_E_ADDI while eliminating the frameindex (#139515)

The QC_E_ADDI instruction from the Xqcilia extension takes a signed
26-bit immediate and can be used instead of splitting the offset across
two ADDI's while eliminating the frameindex.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
    llvm/test/CodeGen/RISCV/stack-offset.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp b/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
index 65a6f54d6c8aa..112142e1ef2f2 100644
--- a/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
@@ -291,6 +291,30 @@ void RISCVRegisterInfo::adjustReg(MachineBasicBlock &MBB,
     return;
   }
 
+  // Use the QC_E_ADDI instruction from the Xqcilia extension that can take a
+  // signed 26-bit immediate.
+  if (ST.hasVendorXqcilia() && isInt<26>(Val)) {
+    // The one case where using this instruction is sub-optimal is if Val can be
+    // materialized with a single compressible LUI and following add/sub is also
+    // compressible. Avoid doing this if that is the case.
+    int Hi20 = (Val & 0xFFFFF000) >> 12;
+    bool IsCompressLUI =
+        ((Val & 0xFFF) == 0) && (Hi20 != 0) &&
+        (isUInt<5>(Hi20) || (Hi20 >= 0xfffe0 && Hi20 <= 0xfffff));
+    bool IsCompressAddSub =
+        (SrcReg == DestReg) &&
+        ((Val > 0 && RISCV::GPRNoX0RegClass.contains(SrcReg)) ||
+         (Val < 0 && RISCV::GPRCRegClass.contains(SrcReg)));
+
+    if (!(IsCompressLUI && IsCompressAddSub)) {
+      BuildMI(MBB, II, DL, TII->get(RISCV::QC_E_ADDI), DestReg)
+          .addReg(SrcReg, getKillRegState(KillSrcReg))
+          .addImm(Val)
+          .setMIFlag(Flag);
+      return;
+    }
+  }
+
   // Try to split the offset across two ADDIs. We need to keep the intermediate
   // result aligned after each ADDI.  We need to determine the maximum value we
   // can put in each ADDI. In the negative direction, we can use -2048 which is

diff  --git a/llvm/test/CodeGen/RISCV/stack-offset.ll b/llvm/test/CodeGen/RISCV/stack-offset.ll
index 402d3546eae29..3dc4fcfe26a82 100644
--- a/llvm/test/CodeGen/RISCV/stack-offset.ll
+++ b/llvm/test/CodeGen/RISCV/stack-offset.ll
@@ -1,6 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s \
 ; RUN:   | FileCheck %s -check-prefixes=RV32,RV32I
+; RUN: llc -mtriple=riscv32 -verify-machineinstrs -mattr=+experimental-xqcilia < %s \
+; RUN:   | FileCheck %s -check-prefixes=RV32XQCILIA
 ; RUN: llc -mtriple=riscv32 -verify-machineinstrs -mattr=+zba < %s \
 ; RUN:   | FileCheck %s -check-prefixes=RV32,RV32ZBA
 ; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
@@ -39,6 +41,27 @@ define void @test() {
 ; RV32I-NEXT:    .cfi_def_cfa_offset 0
 ; RV32I-NEXT:    ret
 ;
+; RV32XQCILIA-LABEL: test:
+; RV32XQCILIA:       # %bb.0:
+; RV32XQCILIA-NEXT:    addi sp, sp, -2032
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 2032
+; RV32XQCILIA-NEXT:    sw ra, 2028(sp) # 4-byte Folded Spill
+; RV32XQCILIA-NEXT:    .cfi_offset ra, -4
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, -3168
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 5200
+; RV32XQCILIA-NEXT:    addi a0, sp, 12
+; RV32XQCILIA-NEXT:    qc.e.addi a1, sp, 2060
+; RV32XQCILIA-NEXT:    qc.e.addi a2, sp, 4108
+; RV32XQCILIA-NEXT:    qc.e.addi a3, sp, 5132
+; RV32XQCILIA-NEXT:    call inspect
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, 3168
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 2032
+; RV32XQCILIA-NEXT:    lw ra, 2028(sp) # 4-byte Folded Reload
+; RV32XQCILIA-NEXT:    .cfi_restore ra
+; RV32XQCILIA-NEXT:    addi sp, sp, 2032
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 0
+; RV32XQCILIA-NEXT:    ret
+;
 ; RV32ZBA-LABEL: test:
 ; RV32ZBA:       # %bb.0:
 ; RV32ZBA-NEXT:    addi sp, sp, -2032
@@ -150,6 +173,25 @@ define void @align_8() {
 ; RV32I-NEXT:    .cfi_def_cfa_offset 0
 ; RV32I-NEXT:    ret
 ;
+; RV32XQCILIA-LABEL: align_8:
+; RV32XQCILIA:       # %bb.0:
+; RV32XQCILIA-NEXT:    addi sp, sp, -256
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 256
+; RV32XQCILIA-NEXT:    sw ra, 252(sp) # 4-byte Folded Spill
+; RV32XQCILIA-NEXT:    .cfi_offset ra, -4
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, -3856
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 4112
+; RV32XQCILIA-NEXT:    addi a0, sp, 7
+; RV32XQCILIA-NEXT:    qc.e.addi a1, sp, 4104
+; RV32XQCILIA-NEXT:    call inspect
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, 3856
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 256
+; RV32XQCILIA-NEXT:    lw ra, 252(sp) # 4-byte Folded Reload
+; RV32XQCILIA-NEXT:    .cfi_restore ra
+; RV32XQCILIA-NEXT:    addi sp, sp, 256
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 0
+; RV32XQCILIA-NEXT:    ret
+;
 ; RV32ZBA-LABEL: align_8:
 ; RV32ZBA:       # %bb.0:
 ; RV32ZBA-NEXT:    addi sp, sp, -2032
@@ -246,6 +288,25 @@ define void @align_4() {
 ; RV32I-NEXT:    .cfi_def_cfa_offset 0
 ; RV32I-NEXT:    ret
 ;
+; RV32XQCILIA-LABEL: align_4:
+; RV32XQCILIA:       # %bb.0:
+; RV32XQCILIA-NEXT:    addi sp, sp, -256
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 256
+; RV32XQCILIA-NEXT:    sw ra, 252(sp) # 4-byte Folded Spill
+; RV32XQCILIA-NEXT:    .cfi_offset ra, -4
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, -3856
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 4112
+; RV32XQCILIA-NEXT:    addi a0, sp, 7
+; RV32XQCILIA-NEXT:    qc.e.addi a1, sp, 4104
+; RV32XQCILIA-NEXT:    call inspect
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, 3856
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 256
+; RV32XQCILIA-NEXT:    lw ra, 252(sp) # 4-byte Folded Reload
+; RV32XQCILIA-NEXT:    .cfi_restore ra
+; RV32XQCILIA-NEXT:    addi sp, sp, 256
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 0
+; RV32XQCILIA-NEXT:    ret
+;
 ; RV32ZBA-LABEL: align_4:
 ; RV32ZBA:       # %bb.0:
 ; RV32ZBA-NEXT:    addi sp, sp, -2032
@@ -342,6 +403,25 @@ define void @align_2() {
 ; RV32-NEXT:    .cfi_def_cfa_offset 0
 ; RV32-NEXT:    ret
 ;
+; RV32XQCILIA-LABEL: align_2:
+; RV32XQCILIA:       # %bb.0:
+; RV32XQCILIA-NEXT:    addi sp, sp, -256
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 256
+; RV32XQCILIA-NEXT:    sw ra, 252(sp) # 4-byte Folded Spill
+; RV32XQCILIA-NEXT:    .cfi_offset ra, -4
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, -3856
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 4112
+; RV32XQCILIA-NEXT:    addi a0, sp, 9
+; RV32XQCILIA-NEXT:    qc.e.addi a1, sp, 4106
+; RV32XQCILIA-NEXT:    call inspect
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, 3856
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 256
+; RV32XQCILIA-NEXT:    lw ra, 252(sp) # 4-byte Folded Reload
+; RV32XQCILIA-NEXT:    .cfi_restore ra
+; RV32XQCILIA-NEXT:    addi sp, sp, 256
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 0
+; RV32XQCILIA-NEXT:    ret
+;
 ; RV64-LABEL: align_2:
 ; RV64:       # %bb.0:
 ; RV64-NEXT:    addi sp, sp, -2032
@@ -395,6 +475,25 @@ define void @align_1() {
 ; RV32-NEXT:    .cfi_def_cfa_offset 0
 ; RV32-NEXT:    ret
 ;
+; RV32XQCILIA-LABEL: align_1:
+; RV32XQCILIA:       # %bb.0:
+; RV32XQCILIA-NEXT:    addi sp, sp, -256
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 256
+; RV32XQCILIA-NEXT:    sw ra, 252(sp) # 4-byte Folded Spill
+; RV32XQCILIA-NEXT:    .cfi_offset ra, -4
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, -3856
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 4112
+; RV32XQCILIA-NEXT:    addi a0, sp, 10
+; RV32XQCILIA-NEXT:    qc.e.addi a1, sp, 4107
+; RV32XQCILIA-NEXT:    call inspect
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, 3856
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 256
+; RV32XQCILIA-NEXT:    lw ra, 252(sp) # 4-byte Folded Reload
+; RV32XQCILIA-NEXT:    .cfi_restore ra
+; RV32XQCILIA-NEXT:    addi sp, sp, 256
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 0
+; RV32XQCILIA-NEXT:    ret
+;
 ; RV64-LABEL: align_1:
 ; RV64:       # %bb.0:
 ; RV64-NEXT:    addi sp, sp, -2032
@@ -422,3 +521,100 @@ define void @align_1() {
   call void (...) @inspect(ptr %p1, ptr %p2)
   ret void
 }
+
+define void @align_1_lui() {
+; RV32-LABEL: align_1_lui:
+; RV32:       # %bb.0:
+; RV32-NEXT:    addi sp, sp, -2032
+; RV32-NEXT:    .cfi_def_cfa_offset 2032
+; RV32-NEXT:    sw ra, 2028(sp) # 4-byte Folded Spill
+; RV32-NEXT:    .cfi_offset ra, -4
+; RV32-NEXT:    lui a0, 1
+; RV32-NEXT:    sub sp, sp, a0
+; RV32-NEXT:    .cfi_def_cfa_offset 6128
+; RV32-NEXT:    addi a0, sp, 8
+; RV32-NEXT:    lui a1, 1
+; RV32-NEXT:    addi a1, a1, 2027
+; RV32-NEXT:    add a1, sp, a1
+; RV32-NEXT:    call inspect
+; RV32-NEXT:    lui a0, 1
+; RV32-NEXT:    add sp, sp, a0
+; RV32-NEXT:    .cfi_def_cfa_offset 2032
+; RV32-NEXT:    lw ra, 2028(sp) # 4-byte Folded Reload
+; RV32-NEXT:    .cfi_restore ra
+; RV32-NEXT:    addi sp, sp, 2032
+; RV32-NEXT:    .cfi_def_cfa_offset 0
+; RV32-NEXT:    ret
+;
+; RV32XQCILIA-LABEL: align_1_lui:
+; RV32XQCILIA:       # %bb.0:
+; RV32XQCILIA-NEXT:    addi sp, sp, -2032
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 2032
+; RV32XQCILIA-NEXT:    sw ra, 2028(sp) # 4-byte Folded Spill
+; RV32XQCILIA-NEXT:    .cfi_offset ra, -4
+; RV32XQCILIA-NEXT:    qc.e.addi sp, sp, -4096
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 6128
+; RV32XQCILIA-NEXT:    addi a0, sp, 8
+; RV32XQCILIA-NEXT:    qc.e.addi a1, sp, 6123
+; RV32XQCILIA-NEXT:    call inspect
+; RV32XQCILIA-NEXT:    lui a0, 1
+; RV32XQCILIA-NEXT:    add sp, sp, a0
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 2032
+; RV32XQCILIA-NEXT:    lw ra, 2028(sp) # 4-byte Folded Reload
+; RV32XQCILIA-NEXT:    .cfi_restore ra
+; RV32XQCILIA-NEXT:    addi sp, sp, 2032
+; RV32XQCILIA-NEXT:    .cfi_def_cfa_offset 0
+; RV32XQCILIA-NEXT:    ret
+;
+; RV64I-LABEL: align_1_lui:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -2032
+; RV64I-NEXT:    .cfi_def_cfa_offset 2032
+; RV64I-NEXT:    sd ra, 2024(sp) # 8-byte Folded Spill
+; RV64I-NEXT:    .cfi_offset ra, -8
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addiw a0, a0, 16
+; RV64I-NEXT:    sub sp, sp, a0
+; RV64I-NEXT:    .cfi_def_cfa_offset 6144
+; RV64I-NEXT:    addi a0, sp, 20
+; RV64I-NEXT:    lui a1, 1
+; RV64I-NEXT:    addiw a1, a1, 2039
+; RV64I-NEXT:    add a1, sp, a1
+; RV64I-NEXT:    call inspect
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addiw a0, a0, 16
+; RV64I-NEXT:    add sp, sp, a0
+; RV64I-NEXT:    .cfi_def_cfa_offset 2032
+; RV64I-NEXT:    ld ra, 2024(sp) # 8-byte Folded Reload
+; RV64I-NEXT:    .cfi_restore ra
+; RV64I-NEXT:    addi sp, sp, 2032
+; RV64I-NEXT:    .cfi_def_cfa_offset 0
+; RV64I-NEXT:    ret
+;
+; RV64ZBA-LABEL: align_1_lui:
+; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    addi sp, sp, -2032
+; RV64ZBA-NEXT:    .cfi_def_cfa_offset 2032
+; RV64ZBA-NEXT:    sd ra, 2024(sp) # 8-byte Folded Spill
+; RV64ZBA-NEXT:    .cfi_offset ra, -8
+; RV64ZBA-NEXT:    li a0, -514
+; RV64ZBA-NEXT:    sh3add sp, a0, sp
+; RV64ZBA-NEXT:    .cfi_def_cfa_offset 6144
+; RV64ZBA-NEXT:    addi a0, sp, 20
+; RV64ZBA-NEXT:    lui a1, 1
+; RV64ZBA-NEXT:    addiw a1, a1, 2039
+; RV64ZBA-NEXT:    add a1, sp, a1
+; RV64ZBA-NEXT:    call inspect
+; RV64ZBA-NEXT:    li a0, 514
+; RV64ZBA-NEXT:    sh3add sp, a0, sp
+; RV64ZBA-NEXT:    .cfi_def_cfa_offset 2032
+; RV64ZBA-NEXT:    ld ra, 2024(sp) # 8-byte Folded Reload
+; RV64ZBA-NEXT:    .cfi_restore ra
+; RV64ZBA-NEXT:    addi sp, sp, 2032
+; RV64ZBA-NEXT:    .cfi_def_cfa_offset 0
+; RV64ZBA-NEXT:    ret
+  %p2 = alloca i8, align 1
+  %p1 = alloca [6115 x i8], align 1
+  call void (...) @inspect(ptr %p1, ptr %p2)
+  ret void
+}


        


More information about the llvm-commits mailing list