[PATCH] D94466: [X86] merge "={eax}" and "~{eax}" into "=&eax" for MSInlineASM

[Freddy, Ye via Phabricator via cfe-commits]

FreddyYe created this revision.
FreddyYe requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D94466

Files:
  clang/lib/CodeGen/CGStmt.cpp
  clang/test/CodeGen/ms-inline-asm.c
  clang/test/CodeGenCXX/ms-inline-asm-return.cpp


Index: clang/test/CodeGenCXX/ms-inline-asm-return.cpp
===================================================================
--- clang/test/CodeGenCXX/ms-inline-asm-return.cpp
+++ clang/test/CodeGenCXX/ms-inline-asm-return.cpp
@@ -23,7 +23,7 @@
   }
 }
 // CHECK-LABEL: define dso_local i32 @f_i32()
-// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$1\0A\09mov edx, $$1", "={eax},~{eax},{{.*}}"
+// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$1\0A\09mov edx, $$1", "=&{eax},{{.*}}"
 // CHECK: ret i32 %[[r]]
 
 short f_i16() {
@@ -33,7 +33,7 @@
   }
 }
 // CHECK-LABEL: define dso_local signext i16 @f_i16()
-// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$1\0A\09mov edx, $$1", "={eax},~{eax},{{.*}}"
+// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$1\0A\09mov edx, $$1", "=&{eax},{{.*}}"
 // CHECK: %[[r_i16:[^ ]*]] = trunc i32 %[[r]] to i16
 // CHECK: ret i16 %[[r_i16]]
 
@@ -44,7 +44,7 @@
   }
 }
 // CHECK-LABEL: define dso_local signext i8 @f_i8()
-// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$1\0A\09mov edx, $$1", "={eax},~{eax},{{.*}}"
+// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$1\0A\09mov edx, $$1", "=&{eax},{{.*}}"
 // CHECK: %[[r_i8:[^ ]*]] = trunc i32 %[[r]] to i8
 // CHECK: ret i8 %[[r_i8]]
 
@@ -55,7 +55,7 @@
   }
 }
 // CHECK-LABEL: define dso_local zeroext i1 @f_i1()
-// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$1\0A\09mov edx, $$1", "={eax},~{eax},{{.*}}"
+// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$1\0A\09mov edx, $$1", "=&{eax},{{.*}}"
 // CHECK: %[[r_i8:[^ ]*]] = trunc i32 %[[r]] to i8
 // CHECK: store i8 %[[r_i8]], i8* %{{.*}}
 // CHECK: %[[r_i1:[^ ]*]] = load i1, i1* %{{.*}}
@@ -70,7 +70,7 @@
   }
 }
 // CHECK-LABEL: define dso_local i32 @f_s4()
-// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$16843009", "={eax},~{eax},{{.*}}"
+// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "mov eax, $$16843009", "=&{eax},{{.*}}"
 // CHECK: store i32 %[[r]], i32* %{{.*}}
 // CHECK: %[[r_i32:[^ ]*]] = load i32, i32* %{{.*}}
 // CHECK: ret i32 %[[r_i32]]
@@ -96,5 +96,5 @@
   __asm xor eax, eax
 }
 // CHECK-LABEL: define dso_local i32 @main()
-// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "xor eax, eax", "={eax},{{.*}}"
+// CHECK: %[[r:[^ ]*]] = call i32 asm sideeffect inteldialect "xor eax, eax", "=&{eax},{{.*}}"
 // CHECK: ret i32 %[[r]]
Index: clang/test/CodeGen/ms-inline-asm.c
===================================================================
--- clang/test/CodeGen/ms-inline-asm.c
+++ clang/test/CodeGen/ms-inline-asm.c
@@ -114,7 +114,7 @@
 // CHECK: call i32 asm sideeffect inteldialect
 // CHECK-SAME: mov eax, $2
 // CHECK-SAME: mov $0, eax
-// CHECK-SAME: "=*m,={eax},*m,~{eax},~{dirflag},~{fpsr},~{flags}"(i32* %{{.*}}, i32* %{{.*}})
+// CHECK-SAME: "=*m,=&{eax},*m,~{dirflag},~{fpsr},~{flags}"(i32* %{{.*}}, i32* %{{.*}})
 // CHECK: [[RET:%[a-zA-Z0-9]+]] = load i32, i32* [[J]], align 4
 // CHECK: ret i32 [[RET]]
 }
@@ -140,7 +140,7 @@
 // CHECK-SAME: mov $0, eax
 // CHECK-SAME: mov eax, $4
 // CHECK-SAME: mov $1, eax
-// CHECK-SAME: "=*m,=*m,={eax},*m,*m,~{eax},~{dirflag},~{fpsr},~{flags}"(i32* %{{.*}}, i32* %{{.*}}, i32* %{{.*}}, i32* %{{.*}})
+// CHECK-SAME: "=*m,=*m,=&{eax},*m,*m,~{dirflag},~{fpsr},~{flags}"(i32* %{{.*}}, i32* %{{.*}}, i32* %{{.*}}, i32* %{{.*}})
 }
 
 void t13() {
Index: clang/lib/CodeGen/CGStmt.cpp
===================================================================
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -2483,6 +2483,15 @@
       }
     }
 
+    if (isa<MSAsmStmt>(&S)) {
+      if (Clobber == "eax") {
+        std::string::size_type position = Constraints.find("={eax}");
+        if (position != std::string::npos) {
+          Constraints.insert(position + 1, "&");
+          break;
+        }
+      }
+    }
     if (!Constraints.empty())
       Constraints += ',';
 


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