[OpenCL] Add 'denorms-are-zero' function attribute

[krisb]

Summary

Generate attribute 'denorms-are-zero'='true' if '-cl-denorms-are-zero'
compile option was specified and 'denorms-are-zero'='false' otherwise.

[Anastasia]

test/CodeGenOpenCL/denorms-are-zero.cl

10

Could we add a check for the false case too?

19–24

Should we check denorms-are-zero here as well?

[krisb]

Applied the comments

[yaxunl]

LGTM. Thanks!

lib/CodeGen/CGCall.cpp

if (AttrOnCallSite) {
     FuncAttrs.addAttribute("stack-protector-buffer-size",
                            llvm::utostr(CodeGenOpts.SSPBufferSize));
     FuncAttrs.addAttribute("no-signed-zeros-fp-math",
                            llvm::toStringRef(CodeGenOpts.NoSignedZeros));
     FuncAttrs.addAttribute(
         "correctly-rounded-divide-sqrt-fp-math",
         llvm::toStringRef(CodeGenOpts.CorrectlyRoundedDivSqrt));
 
+    if (getLangOpts().OpenCL)
+      FuncAttrs.addAttribute("denorms-are-zero",
+                             llvm::toStringRef(CodeGenOpts.FlushDenorm));
+
     // TODO: Reciprocal estimate codegen options should apply to instructions?
     const std::vector<std::string> &Recips = CodeGenOpts.Reciprocals;
     if (!Recips.empty())
       FuncAttrs.addAttribute("reciprocal-estimates",
                              llvm::join(Recips, ","));
 
     if (!CodeGenOpts.PreferVectorWidth.empty() &&
         CodeGenOpts.PreferVectorWidth != "none")

test/CodeGenOpenCL/denorms-are-zero.cl

-// RUN: %clang_cc1 -S -cl-denorms-are-zero -o - %s 2>&1
-// RUN: %clang_cc1 -emit-llvm -cl-denorms-are-zero -o - -triple amdgcn--amdhsa -target-cpu fiji %s | FileCheck %s
-// RUN: %clang_cc1 -emit-llvm -o - -triple amdgcn--amdhsa -target-cpu fiji %s | FileCheck %s --check-prefix=CHECK-DENORM
-// RUN: %clang_cc1 -emit-llvm -target-feature +fp32-denormals -target-feature -fp64-fp16-denormals -cl-denorms-are-zero -o - -triple amdgcn--amdhsa -target-cpu fiji %s | FileCheck --check-prefix=CHECK-FEATURE %s
+// RUN: %clang_cc1 -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -emit-llvm -cl-denorms-are-zero -o - %s | FileCheck %s --check-prefix=DENORM-ZERO
+// RUN: %clang_cc1 -emit-llvm -cl-denorms-are-zero -o - -triple amdgcn--amdhsa -target-cpu fiji %s | FileCheck %s --check-prefix=AMDGCN
+// RUN: %clang_cc1 -emit-llvm -o - -triple amdgcn--amdhsa -target-cpu fiji %s | FileCheck %s --check-prefix=AMDGCN-DENORM
+// RUN: %clang_cc1 -emit-llvm -target-feature +fp32-denormals -target-feature -fp64-fp16-denormals -cl-denorms-are-zero -o - -triple amdgcn--amdhsa -target-cpu fiji %s | FileCheck --check-prefix=AMDGCN-FEATURE %s
 
-// For non-amdgcn targets, this test just checks that the -cl-denorms-are-zero argument is accepted
-// by clang.  This option is currently a no-op, which is allowed by the
-// OpenCL specification.
+// For all targets 'denorms-are-zero' attribute is set to 'true'
+// if '-cl-denorms-are-zero' was specified and  to 'false' otherwise.
+
+// CHECK-LABEL: define void @f()
+// CHECK: attributes #{{[0-9]*}} = {{{[^}]*}} "denorms-are-zero"="false"
+//
+// DENORM-ZERO-LABEL: define void @f()
+// DENORM-ZERO: attributes #{{[0-9]*}} = {{{[^}]*}} "denorms-are-zero"="true"
 
 // For amdgcn target cpu fiji, fp32 should be flushed since fiji does not support fp32 denormals, unless +fp32-denormals is
 // explicitly set. amdgcn target always do not flush fp64 denormals. The control for fp64 and fp16 denormals is the same.
 
-// CHECK-DENORM-LABEL: define void @f()
-// CHECK-DENORM: attributes #{{[0-9]*}} = {{{[^}]*}} "target-features"="{{[^"]*}}+fp64-fp16-denormals,{{[^"]*}}-fp32-denormals{{[^"]*}}"
-// CHECK-LABEL: define void @f()
-// CHECK: attributes #{{[0-9]*}} = {{{[^}]*}} "target-features"="{{[^"]*}}+fp64-fp16-denormals,{{[^"]*}}-fp32-denormals{{[^"]*}}"
-// CHECK-FEATURE-LABEL: define void @f()
-// CHECK-FEATURE: attributes #{{[0-9]*}} = {{{[^}]*}} "target-features"="{{[^"]*}}+fp32-denormals,{{[^"]*}}-fp64-fp16-denormals{{[^"]*}}"
+// AMDGCN-LABEL: define void @f()
+// AMDGCN: attributes #{{[0-9]*}} = {{{[^}]*}} "denorms-are-zero"="true" {{.*}} "target-features"="{{[^"]*}}+fp64-fp16-denormals,{{[^"]*}}-fp32-denormals{{[^"]*}}"
+// AMDGCN-DENORM-LABEL: define void @f()
+// AMDGCN-DENORM: attributes #{{[0-9]*}} = {{{[^}]*}} "denorms-are-zero"="false" {{.*}} "target-features"="{{[^"]*}}+fp64-fp16-denormals,{{[^"]*}}-fp32-denormals{{[^"]*}}"
+// AMDGCN-FEATURE-LABEL: define void @f()
+// AMDGCN-FEATURE: attributes #{{[0-9]*}} = {{{[^}]*}} "denorms-are-zero"="true" {{.*}} "target-features"="{{[^"]*}}+fp32-denormals,{{[^"]*}}-fp64-fp16-denormals{{[^"]*}}"
 void f() {}