[LoongArch] Support amcas[_db].{b/h/w/d} instructions.

clang/include/clang/Driver/Options.td

@@ -5413,6 +5413,10 @@ def mlam_bh : Flag<["-"], "mlam-bh">, Group<m_loongarch_Features_Group>,
   HelpText<"Enable amswap[_db].{b/h} and amadd[_db].{b/h}">;
 def mno_lam_bh : Flag<["-"], "mno-lam-bh">, Group<m_loongarch_Features_Group>,
   HelpText<"Disable amswap[_db].{b/h} and amadd[_db].{b/h}">;
+def mlamcas : Flag<["-"], "mlamcas">, Group<m_loongarch_Features_Group>,
+  HelpText<"Enable amcas[_db].{b/h/w/d}">;
+def mno_lamcas : Flag<["-"], "mno-lamcas">, Group<m_loongarch_Features_Group>,
+  HelpText<"Disable amcas[_db].{b/h/w/d}">;
 def mld_seq_sa : Flag<["-"], "mld-seq-sa">, Group<m_loongarch_Features_Group>,
   HelpText<"Do not generate load-load barrier instructions (dbar 0x700)">;
 def mno_ld_seq_sa : Flag<["-"], "mno-ld-seq-sa">, Group<m_loongarch_Features_Group>,

clang/lib/Basic/Targets/LoongArch.cpp

@@ -205,8 +205,8 @@ void LoongArchTargetInfo::getTargetDefines(const LangOptions &Opts,
       // TODO: As more features of the V1.1 ISA are supported, a unified "v1.1"
       // arch feature set will be used to include all sub-features belonging to
       // the V1.1 ISA version.
-      if (HasFeatureFrecipe && HasFeatureLAM_BH && HasFeatureLD_SEQ_SA &&
-          HasFeatureDiv32)
+      if (HasFeatureFrecipe && HasFeatureLAM_BH && HasFeatureLAMCAS &&
+          HasFeatureLD_SEQ_SA && HasFeatureDiv32)
         Builder.defineMacro("__loongarch_arch",
                             Twine('"') + "la64v1.1" + Twine('"'));
       else
@@ -240,6 +240,9 @@ void LoongArchTargetInfo::getTargetDefines(const LangOptions &Opts,
   if (HasFeatureLAM_BH)
     Builder.defineMacro("__loongarch_lam_bh", Twine(1));
 
+  if (HasFeatureLAMCAS)
+    Builder.defineMacro("__loongarch_lamcas", Twine(1));
+
   if (HasFeatureLD_SEQ_SA)
     Builder.defineMacro("__loongarch_ld_seq_sa", Twine(1));
 
@@ -324,6 +327,8 @@ bool LoongArchTargetInfo::handleTargetFeatures(
       HasFeatureFrecipe = true;
     else if (Feature == "+lam-bh")
       HasFeatureLAM_BH = true;
+    else if (Feature == "+lamcas")
+      HasFeatureLAMCAS = true;
     else if (Feature == "+ld-seq-sa")
       HasFeatureLD_SEQ_SA = true;
     else if (Feature == "+div32")

clang/lib/Basic/Targets/LoongArch.h

@@ -31,6 +31,7 @@ class LLVM_LIBRARY_VISIBILITY LoongArchTargetInfo : public TargetInfo {
   bool HasFeatureLASX;
   bool HasFeatureFrecipe;
   bool HasFeatureLAM_BH;
+  bool HasFeatureLAMCAS;
   bool HasFeatureLD_SEQ_SA;
   bool HasFeatureDiv32;
 
@@ -43,6 +44,7 @@ class LLVM_LIBRARY_VISIBILITY LoongArchTargetInfo : public TargetInfo {
     HasFeatureLASX = false;
     HasFeatureFrecipe = false;
     HasFeatureLAM_BH = false;
+    HasFeatureLAMCAS = false;
     HasFeatureLD_SEQ_SA = false;
     HasFeatureDiv32 = false;
     LongDoubleWidth = 128;

clang/lib/Driver/ToolChains/Arch/LoongArch.cpp

@@ -275,6 +275,15 @@ void loongarch::getLoongArchTargetFeatures(const Driver &D,
       Features.push_back("-lam-bh");
   }
 
+  // Select lamcas feature determined by -m[no-]lamcas.
+  if (const Arg *A =
+          Args.getLastArg(options::OPT_mlamcas, options::OPT_mno_lamcas)) {
+    if (A->getOption().matches(options::OPT_mlamcas))
+      Features.push_back("+lamcas");
+    else
+      Features.push_back("-lamcas");
+  }
+
   // Select ld-seq-sa feature determined by -m[no-]ld-seq-sa.
   if (const Arg *A = Args.getLastArg(options::OPT_mld_seq_sa,
                                      options::OPT_mno_ld_seq_sa)) {

clang/test/Driver/loongarch-march.c

@@ -39,21 +39,21 @@
 
 // CC1-LA64V1P1: "-target-cpu" "loongarch64"
 // CC1-LA64V1P1-NOT: "-target-feature"
-// CC1-LA64V1P1: "-target-feature" "+64bit" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+ual" "-target-feature" "+frecipe" "-target-feature" "+lam-bh" "-target-feature" "+ld-seq-sa" "-target-feature" "+div32"
+// CC1-LA64V1P1: "-target-feature" "+64bit" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+ual" "-target-feature" "+frecipe" "-target-feature" "+lam-bh" "-target-feature" "+lamcas" "-target-feature" "+ld-seq-sa" "-target-feature" "+div32"
 // CC1-LA64V1P1-NOT: "-target-feature"
 // CC1-LA64V1P1: "-target-abi" "lp64d"
 
 // CC1-LA664: "-target-cpu" "la664"
 // CC1-LA664-NOT: "-target-feature"
-// CC1-LA664: "-target-feature" "+64bit" "-target-feature" "+f" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+lasx" "-target-feature" "+ual" "-target-feature" "+frecipe" "-target-feature" "+lam-bh" "-target-feature" "+ld-seq-sa" "-target-feature" "+div32"
+// CC1-LA664: "-target-feature" "+64bit" "-target-feature" "+f" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+lasx" "-target-feature" "+ual" "-target-feature" "+frecipe" "-target-feature" "+lam-bh" "-target-feature" "+lamcas" "-target-feature" "+ld-seq-sa" "-target-feature" "+div32"
 // CC1-LA664-NOT: "-target-feature"
 // CC1-LA664: "-target-abi" "lp64d"
 
 // IR-LOONGARCH64: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+f,+ual"
 // IR-LA464: attributes #[[#]] ={{.*}}"target-cpu"="la464" {{.*}}"target-features"="+64bit,+d,+f,+lasx,+lsx,+ual"
 // IR-LA64V1P0: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+lsx,+ual"
-// IR-LA64V1P1: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+div32,+frecipe,+lam-bh,+ld-seq-sa,+lsx,+ual"
-// IR-LA664: attributes #[[#]] ={{.*}}"target-cpu"="la664" {{.*}}"target-features"="+64bit,+d,+div32,+f,+frecipe,+lam-bh,+lasx,+ld-seq-sa,+lsx,+ual"
+// IR-LA64V1P1: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+div32,+frecipe,+lam-bh,+lamcas,+ld-seq-sa,+lsx,+ual"
+// IR-LA664: attributes #[[#]] ={{.*}}"target-cpu"="la664" {{.*}}"target-features"="+64bit,+d,+div32,+f,+frecipe,+lam-bh,+lamcas,+lasx,+ld-seq-sa,+lsx,+ual"
 
 int foo(void) {
   return 3;

clang/test/Driver/loongarch-mlamcas.c

@@ -0,0 +1,30 @@
+/// Test -m[no]lamcas options.
+
+// RUN: %clang --target=loongarch64 -mlamcas -fsyntax-only %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CC1-LAMCAS
+// RUN: %clang --target=loongarch64 -mno-lamcas -fsyntax-only %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CC1-NO-LAMCAS
+// RUN: %clang --target=loongarch64 -mno-lamcas -mlamcas -fsyntax-only %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CC1-LAMCAS
+// RUN: %clang --target=loongarch64  -mlamcas -mno-lamcas -fsyntax-only %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CC1-NO-LAMCAS
+
+// RUN: %clang --target=loongarch64 -mlamcas -S -emit-llvm %s -o - | \
+// RUN: FileCheck %s --check-prefix=IR-LAMCAS
+// RUN: %clang --target=loongarch64 -mno-lamcas -S -emit-llvm %s -o - | \
+// RUN: FileCheck %s --check-prefix=IR-NO-LAMCAS
+// RUN: %clang --target=loongarch64 -mno-lamcas -mlamcas -S -emit-llvm %s -o - | \
+// RUN: FileCheck %s --check-prefix=IR-LAMCAS
+// RUN: %clang --target=loongarch64 -mlamcas -mno-lamcas -S -emit-llvm %s -o - | \
+// RUN: FileCheck %s --check-prefix=IR-NO-LAMCAS
+
+
+// CC1-LAMCAS: "-target-feature" "+lamcas"
+// CC1-NO-LAMCAS: "-target-feature" "-lamcas"
+
+// IR-LAMCAS: attributes #[[#]] ={{.*}}"target-features"="{{(.*,)?}}+lamcas{{(,.*)?}}"
+// IR-NO-LAMCAS: attributes #[[#]] ={{.*}}"target-features"="{{(.*,)?}}-lamcas{{(,.*)?}}"
+
+int foo(void) {
+  return 42;
+}

clang/test/Preprocessor/init-loongarch.c

@@ -798,7 +798,7 @@
 // LA64-FPU0-LP64S-NOT: #define __loongarch_single_float
 // LA64-FPU0-LP64S: #define __loongarch_soft_float 1
 
-/// Check __loongarch_arch{_tune/_frecipe/_lam_bh/_ld_seq_sa/_div32}.
+/// Check __loongarch_arch{_tune/_frecipe/_lam_bh/_lamcas/_ld_seq_sa/_div32}.
 
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - | \
 // RUN:   FileCheck --match-full-lines --check-prefix=ARCH-TUNE -DARCH=la64v1.0 -DTUNE=loongarch64 %s
@@ -823,54 +823,63 @@
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +lsx | \
 // RUN:   FileCheck --match-full-lines --check-prefix=ARCH-TUNE -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.1 | \
-// RUN:   FileCheck --match-full-lines  --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LD-SEQ-SA,DIV32 -DARCH=la64v1.1 -DTUNE=loongarch64 %s
+// RUN:   FileCheck --match-full-lines  --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LAMCAS,LD-SEQ-SA,DIV32 -DARCH=la64v1.1 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.1 -Xclang -target-feature -Xclang -frecipe | \
-// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LAM-BH,LD-SEQ-SA,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LAM-BH,LAMCAS,LD-SEQ-SA,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.1 -Xclang -target-feature -Xclang -lsx | \
-// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LD-SEQ-SA,DIV32 -DARCH=loongarch64 -DTUNE=loongarch64 %s
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LAMCAS,LD-SEQ-SA,DIV32 -DARCH=loongarch64 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +frecipe | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE -DARCH=loongarch64 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +lsx -Xclang -target-feature -Xclang +frecipe | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.0 -Xclang -target-feature -Xclang +lam-bh | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LAM-BH -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.1 -Xclang -target-feature -Xclang -lam-bh | \
-// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LD-SEQ-SA,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAMCAS,LD-SEQ-SA,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +lam-bh | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LAM-BH -DARCH=loongarch64 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +lsx -Xclang -target-feature -Xclang +lam-bh | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LAM-BH -DARCH=la64v1.0 -DTUNE=loongarch64 %s
+// RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.0 -Xclang -target-feature -Xclang +lamcas | \
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LAMCAS -DARCH=la64v1.0 -DTUNE=loongarch64 %s
+// RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.1 -Xclang -target-feature -Xclang -lamcas | \
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LD-SEQ-SA,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
+// RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +lamcas | \
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LAMCAS -DARCH=loongarch64 -DTUNE=loongarch64 %s
+// RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +lsx -Xclang -target-feature -Xclang +lamcas | \
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LAMCAS -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.0 -Xclang -target-feature -Xclang +ld-seq-sa | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LD-SEQ-SA -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.1 -Xclang -target-feature -Xclang -ld-seq-sa | \
-// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LAMCAS,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +ld-seq-sa | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LD-SEQ-SA -DARCH=loongarch64 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +lsx -Xclang -target-feature -Xclang +ld-seq-sa | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,LD-SEQ-SA -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.0 -Xclang -target-feature -Xclang +div32 | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.1 -Xclang -target-feature -Xclang -div32| \
-// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LD-SEQ-SA -DARCH=la64v1.0 -DTUNE=loongarch64 %s
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LAMCAS,LD-SEQ-SA -DARCH=la64v1.0 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +div32 | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,DIV32 -DARCH=loongarch64 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -Xclang -target-feature -Xclang +lsx -Xclang -target-feature -Xclang +div32 | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,DIV32 -DARCH=la64v1.0 -DTUNE=loongarch64 %s
-// RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.0 -Xclang -target-feature -Xclang +frecipe -Xclang -target-feature -Xclang +lam-bh  -Xclang -target-feature -Xclang +ld-seq-sa -Xclang -target-feature -Xclang +div32 | \
+// RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la64v1.0 -Xclang -target-feature -Xclang +frecipe -Xclang -target-feature -Xclang +lam-bh  -Xclang -target-feature -Xclang +lamcas -Xclang -target-feature -Xclang +ld-seq-sa -Xclang -target-feature -Xclang +div32 | \
 // RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE -DARCH=la64v1.1 -DTUNE=loongarch64 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la664 | \
-// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LD-SEQ-SA,DIV32 -DARCH=la664 -DTUNE=la664 %s
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LAMCAS,LD-SEQ-SA,DIV32 -DARCH=la664 -DTUNE=la664 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -mtune=la664 | \
 // RUN:   FileCheck --match-full-lines --check-prefix=ARCH-TUNE -DARCH=la64v1.0 -DTUNE=la664 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=loongarch64 -mtune=la664 | \
 // RUN:   FileCheck --match-full-lines --check-prefix=ARCH-TUNE -DARCH=loongarch64 -DTUNE=la664 %s
 // RUN: %clang --target=loongarch64 -x c -E -dM %s -o - -march=la664 -mtune=loongarch64 | \
-// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LD-SEQ-SA,DIV32 -DARCH=la664 -DTUNE=loongarch64 %s
+// RUN:   FileCheck --match-full-lines --check-prefixes=ARCH-TUNE,FRECIPE,LAM-BH,LAMCAS,LD-SEQ-SA,DIV32 -DARCH=la664 -DTUNE=loongarch64 %s
 
 // ARCH-TUNE: #define __loongarch_arch "[[ARCH]]"
 // DIV32: #define __loongarch_div32 1
 // FRECIPE: #define __loongarch_frecipe 1
 // LAM-BH: #define __loongarch_lam_bh 1
+// LAMCAS: #define __loongarch_lamcas 1
 // LD-SEQ-SA: #define __loongarch_ld_seq_sa 1
 // ARCH-TUNE: #define __loongarch_tune "[[TUNE]]"
 

llvm/include/llvm/TargetParser/LoongArchTargetParser.def

@@ -12,6 +12,7 @@ LOONGARCH_FEATURE("+lvz", FK_LVZ)
 LOONGARCH_FEATURE("+ual", FK_UAL)
 LOONGARCH_FEATURE("+frecipe", FK_FRECIPE)
 LOONGARCH_FEATURE("+lam-bh", FK_LAM_BH)
+LOONGARCH_FEATURE("+lamcas", FK_LAMCAS)
 LOONGARCH_FEATURE("+ld-seq-sa", FK_LD_SEQ_SA)
 LOONGARCH_FEATURE("+div32", FK_DIV32)
 
@@ -23,6 +24,6 @@ LOONGARCH_FEATURE("+div32", FK_DIV32)
 
 LOONGARCH_ARCH("loongarch64", AK_LOONGARCH64, FK_64BIT | FK_FP32 | FK_FP64 | FK_UAL)
 LOONGARCH_ARCH("la464", AK_LA464, FK_64BIT | FK_FP32 | FK_FP64 | FK_LSX | FK_LASX | FK_UAL)
-LOONGARCH_ARCH("la664", AK_LA664, FK_64BIT | FK_FP32 | FK_FP64 | FK_LSX | FK_LASX | FK_UAL | FK_FRECIPE | FK_LAM_BH | FK_LD_SEQ_SA | FK_DIV32)
+LOONGARCH_ARCH("la664", AK_LA664, FK_64BIT | FK_FP32 | FK_FP64 | FK_LSX | FK_LASX | FK_UAL | FK_FRECIPE | FK_LAM_BH | FK_LAMCAS | FK_LD_SEQ_SA | FK_DIV32)
 
 #undef LOONGARCH_ARCH

llvm/include/llvm/TargetParser/LoongArchTargetParser.h

@@ -54,6 +54,10 @@ enum FeatureKind : uint32_t {
   // available.
   FK_LAM_BH = 1 << 10,
 
+  // Atomic memory compare and swap instructions for byte, half word, word and
+  // double word are available.
+  FK_LAMCAS = 1 << 11,
+
   // Do not generate load-load barrier instructions (dbar 0x700).
   FK_LD_SEQ_SA = 1 << 12,
 

llvm/lib/Target/LoongArch/LoongArch.td

@@ -118,6 +118,12 @@ def FeatureLAM_BH
                         "Support amswap[_db].{b/h} and amadd[_db].{b/h} instructions.">;
 def HasLAM_BH : Predicate<"Subtarget->hasLAM_BH()">;
 
+// Atomic memory compare and swap instructions for byte, half word, word and double word
+def FeatureLAMCAS
+    : SubtargetFeature<"lamcas", "HasLAMCAS", "true",
+                        "Support amcas[_db].{b/h/w/d}.">;
+def HasLAMCAS : Predicate<"Subtarget->hasLAMCAS()">;
+
 def FeatureLD_SEQ_SA
     : SubtargetFeature<"ld-seq-sa", "HasLD_SEQ_SA", "true",
                         "Don't use load-load barrier (dbar 0x700).">;
@@ -172,6 +178,8 @@ def : ProcessorModel<"la664", NoSchedModel, [Feature64Bit,
                                              FeatureExtLBT,
                                              FeatureFrecipe,
                                              FeatureLAM_BH,
+                                             FeatureLAMCAS,
+                                             FeatureLD_SEQ_SA,
                                              FeatureDiv32]>;
 
 //===----------------------------------------------------------------------===//