[llvm] [RISCV] Compress shxadd to qc.c.muliadd when rd = rs2 (PR #155843)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-risc-v

Author: Sudharsan Veeravalli (svs-quic)

<details>
<summary>Changes</summary>

Do this when Zba and Xqciac are both enabled.

---
Full diff: https://github.com/llvm/llvm-project/pull/155843.diff


2 Files Affected:

- (modified) llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td (+9) 
- (modified) llvm/test/MC/RISCV/xqciac-valid.s (+20-6) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td b/llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td
index 2c64b0c220fba..5c267bf3c8afc 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td
@@ -1743,6 +1743,15 @@ def : CompressPat<(QC_MULIADD GPRC:$rd, GPRC:$rs1, uimm5:$imm5),
                   (QC_C_MULIADD GPRC:$rd, GPRC:$rs1, uimm5:$imm5)>;
 }
 
+let Predicates = [HasVendorXqciac, HasStdExtZba, IsRV32] in {
+def : CompressPat<(SH1ADD GPRC:$rd, GPRC:$rs1, GPRC:$rd),
+                  (QC_C_MULIADD GPRC:$rd, GPRC:$rs1, 2)>;
+def : CompressPat<(SH2ADD GPRC:$rd, GPRC:$rs1, GPRC:$rd),
+                  (QC_C_MULIADD GPRC:$rd, GPRC:$rs1, 4)>;
+def : CompressPat<(SH3ADD GPRC:$rd, GPRC:$rs1, GPRC:$rd),
+                  (QC_C_MULIADD GPRC:$rd, GPRC:$rs1, 8)>;
+}
+
 let isCompressOnly = true, Predicates = [HasVendorXqcibi, IsRV32] in {
 def : CompressPat<(QC_E_BEQI GPRNoX0:$rs1, simm5nonzero:$imm5, bare_simm13_lsb0:$imm12),
                   (QC_BEQI GPRNoX0:$rs1, simm5nonzero:$imm5, bare_simm13_lsb0:$imm12)>;
diff --git a/llvm/test/MC/RISCV/xqciac-valid.s b/llvm/test/MC/RISCV/xqciac-valid.s
index 1afebc75cb45a..dd0848358c149 100644
--- a/llvm/test/MC/RISCV/xqciac-valid.s
+++ b/llvm/test/MC/RISCV/xqciac-valid.s
@@ -1,13 +1,13 @@
 # Xqciac - Qualcomm uC Load-Store Address Calculation Extension
-# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-xqciac -M no-aliases -show-encoding \
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-xqciac,+zba -M no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ENC,CHECK-INST,CHECK-NOALIAS %s
-# RUN: llvm-mc -filetype=obj -triple riscv32 -mattr=+experimental-xqciac < %s \
-# RUN:     | llvm-objdump --mattr=+experimental-xqciac -M no-aliases --no-print-imm-hex -d - \
+# RUN: llvm-mc -filetype=obj -triple riscv32 -mattr=+experimental-xqciac,+zba < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-xqciac,+zba -M no-aliases --no-print-imm-hex -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST %s
-# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-xqciac -show-encoding \
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-xqciac,+zba -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ENC,CHECK-INST,CHECK-ALIAS %s
-# RUN: llvm-mc -filetype=obj -triple riscv32 -mattr=+experimental-xqciac < %s \
-# RUN:     | llvm-objdump --mattr=+experimental-xqciac --no-print-imm-hex -d - \
+# RUN: llvm-mc -filetype=obj -triple riscv32 -mattr=+experimental-xqciac,+zba < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-xqciac,+zba --no-print-imm-hex -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST %s
 
 # CHECK-NOALIAS: qc.c.muliadd    a0, a1, 0
@@ -58,3 +58,17 @@ qc.shladd x10, x11, x12, 31
 # CHECK-ENC: encoding: [0xaa,0x21]
 qc.muliadd x10, x11, 16
 
+# CHECK-NOALIAS: qc.c.muliadd    a0, a1, 2
+# CHECK-ALIAS: qc.muliadd    a0, a1, 2
+# CHECK-ENC: encoding: [0x8a,0x25]
+sh1add x10, x11, x10
+
+# CHECK-NOALIAS: qc.c.muliadd    a0, a1, 4
+# CHECK-ALIAS: qc.muliadd    a0, a1, 4
+# CHECK-ENC: encoding: [0x8a,0x29]
+sh2add x10, x11, x10
+
+# CHECK-NOALIAS: qc.c.muliadd    a0, a1, 8
+# CHECK-ALIAS: qc.muliadd    a0, a1, 8
+# CHECK-ENC: encoding: [0x8a,0x31]
+sh3add x10, x11, x10

``````````

</details>


https://github.com/llvm/llvm-project/pull/155843