[llvm] 390fbe6 - [RISCV] Use Predicates instead of Added Complexity to prefer QC_SELECTEQI over QC_MVEQI. NFC (#148312)

[via llvm-commits]

Author: Craig Topper
Date: 2025-07-11T22:34:54-07:00
New Revision: 390fbe664c8549b8015203eb2d0042cafe223676

URL: https://github.com/llvm/llvm-project/commit/390fbe664c8549b8015203eb2d0042cafe223676
DIFF: https://github.com/llvm/llvm-project/commit/390fbe664c8549b8015203eb2d0042cafe223676.diff

LOG: [RISCV] Use Predicates instead of Added Complexity to prefer QC_SELECTEQI over QC_MVEQI. NFC (#148312)

IMHO AddedComplexity should be used as a last resort. We should use
other mechanism like Predicates and PatFrag predicates to give priority.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVFeatures.td
    llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/RISCVFeatures.td b/llvm/lib/Target/RISCV/RISCVFeatures.td
index bf58226e0bd39..f74f1e06d66a2 100644
--- a/llvm/lib/Target/RISCV/RISCVFeatures.td
+++ b/llvm/lib/Target/RISCV/RISCVFeatures.td
@@ -1487,6 +1487,8 @@ def HasVendorXqcics
     : Predicate<"Subtarget->hasVendorXqcics()">,
       AssemblerPredicate<(all_of FeatureVendorXqcics),
                          "'Xqcics' (Qualcomm uC Conditional Select Extension)">;
+def NoVendorXqcics
+    : Predicate<"!Subtarget->hasVendorXqcics()">;
 
 def FeatureVendorXqcicsr
     : RISCVExperimentalExtension<0, 4, "Qualcomm uC CSR Extension">;

diff  --git a/llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td b/llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td
index add54a7da09cb..4fc98385b4e00 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoXqci.td
@@ -1484,12 +1484,16 @@ def : QCIMVCCPat <SETNE,  QC_MVNE>;
 def : QCIMVCCPat <SETLT,  QC_MVLT>;
 def : QCIMVCCPat <SETULT, QC_MVLTU>;
 
-def : QCIMVCCIPat <SETEQ,  QC_MVEQI, simm5>;
-def : QCIMVCCIPat <SETNE,  QC_MVNEI, simm5>;
 def : QCIMVCCIPat <SETLT,  QC_MVLTI, simm5>;
 def : QCIMVCCIPat <SETULT, QC_MVLTUI, uimm5>;
 }
 
+// Prioritize Xqcics over these patterns.
+let Predicates = [HasVendorXqcicm, NoVendorXqcics, IsRV32] in {
+def : QCIMVCCIPat <SETEQ,  QC_MVEQI, simm5>;
+def : QCIMVCCIPat <SETNE,  QC_MVNEI, simm5>;
+}
+
 let Predicates = [HasVendorXqcics, IsRV32] in {
 def : Pat<(select (i32 GPRNoX0:$rd), (i32 GPRNoX0:$rs2),(i32 GPRNoX0:$rs3)),
           (QC_SELECTNEI GPRNoX0:$rd, (i32 0), GPRNoX0:$rs2, GPRNoX0:$rs3)>;
@@ -1498,12 +1502,8 @@ def : Pat<(select (i32 GPRNoX0:$rd), (i32 GPRNoX0:$rs2), simm5:$simm2),
 def : Pat<(select (i32 GPRNoX0:$rd), simm5:$simm2,(i32 GPRNoX0:$rs2)),
           (QC_SELECTIEQI GPRNoX0:$rd, (i32 0), GPRNoX0:$rs2, simm5:$simm2)>;
 
-// Below AddedComplexity is added to prefer these conditional select instructions over
-// conditional move instructions
-let AddedComplexity = 1 in {
 def : QCISELECTCCIPat <SETEQ,  QC_SELECTEQI>;
 def : QCISELECTCCIPat <SETNE,  QC_SELECTNEI>;
-}
 
 def : QCISELECTICCIPat <SETEQ,  QC_SELECTIEQI>;
 def : QCISELECTICCIPat <SETNE,  QC_SELECTINEI>;