[PATCH] D87888: [X86] Use inlineasm flag output for the _bittest* intrinsics.

[Craig Topper via Phabricator via cfe-commits]

craig.topper created this revision.
craig.topper added reviewers: rnk, niravd.
Herald added a project: clang.
craig.topper requested review of this revision.

Instead of expliciting emitting a setc in the inline asm instructions,
we can use flag output. This allows the backend to use the flag
directly if it is needed by a branch. Previously we needed a test
instruction to convert the register back to a flag.

If the flag can't be used directly, the backend will emit a setcc.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D87888

Files:
  clang/lib/CodeGen/CGBuiltin.cpp
  clang/test/CodeGen/bittest-intrin.c


Index: clang/test/CodeGen/bittest-intrin.c
===================================================================
--- clang/test/CodeGen/bittest-intrin.c
+++ clang/test/CodeGen/bittest-intrin.c
@@ -34,20 +34,20 @@
 #endif
 
 // X64-LABEL: define dso_local void @test32(i32* %base, i32 %idx)
-// X64: call i8 asm sideeffect "btl $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
-// X64: call i8 asm sideeffect "btcl $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
-// X64: call i8 asm sideeffect "btrl $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
-// X64: call i8 asm sideeffect "btsl $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
-// X64: call i8 asm sideeffect "lock btrl $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
-// X64: call i8 asm sideeffect "lock btsl $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
+// X64: call i8 asm sideeffect "btl $2, ($1)", "={@ccc},r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
+// X64: call i8 asm sideeffect "btcl $2, ($1)", "={@ccc},r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
+// X64: call i8 asm sideeffect "btrl $2, ($1)", "={@ccc},r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
+// X64: call i8 asm sideeffect "btsl $2, ($1)", "={@ccc},r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
+// X64: call i8 asm sideeffect "lock btrl $2, ($1)", "={@ccc},r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
+// X64: call i8 asm sideeffect "lock btsl $2, ($1)", "={@ccc},r,r,~{{.*}}"(i32* %{{.*}}, i32 {{.*}})
 
 // X64-LABEL: define dso_local void @test64(i64* %base, i64 %idx)
-// X64: call i8 asm sideeffect "btq $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
-// X64: call i8 asm sideeffect "btcq $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
-// X64: call i8 asm sideeffect "btrq $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
-// X64: call i8 asm sideeffect "btsq $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
-// X64: call i8 asm sideeffect "lock btrq $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
-// X64: call i8 asm sideeffect "lock btsq $2, ($1)\0A\09setc ${0:b}", "=r,r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
+// X64: call i8 asm sideeffect "btq $2, ($1)", "={@ccc},r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
+// X64: call i8 asm sideeffect "btcq $2, ($1)", "={@ccc},r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
+// X64: call i8 asm sideeffect "btrq $2, ($1)", "={@ccc},r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
+// X64: call i8 asm sideeffect "btsq $2, ($1)", "={@ccc},r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
+// X64: call i8 asm sideeffect "lock btrq $2, ($1)", "={@ccc},r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
+// X64: call i8 asm sideeffect "lock btsq $2, ($1)", "={@ccc},r,r,~{{.*}}"(i64* %{{.*}}, i64 {{.*}})
 
 // ARM-LABEL: define dso_local {{.*}}void @test32(i32* %base, i32 %idx)
 // ARM: %[[IDXHI:[^ ]*]] = ashr i32 %{{.*}}, 3
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -805,10 +805,10 @@
   AsmOS << "bt";
   if (Action)
     AsmOS << Action;
-  AsmOS << SizeSuffix << " $2, ($1)\n\tsetc ${0:b}";
+  AsmOS << SizeSuffix << " $2, ($1)";
 
   // Build the constraints. FIXME: We should support immediates when possible.
-  std::string Constraints = "=r,r,r,~{cc},~{flags},~{fpsr}";
+  std::string Constraints = "={@ccc},r,r,~{cc},~{flags},~{fpsr}";
   llvm::IntegerType *IntType = llvm::IntegerType::get(
       CGF.getLLVMContext(),
       CGF.getContext().getTypeSize(E->getArg(1)->getType()));


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