r356571 - [OpenCL] Generate 'unroll.enable' metadata for __attribute__((opencl_unroll_hint))

[Andrew Savonichev via cfe-commits]

Author: asavonic
Date: Wed Mar 20 09:43:07 2019
New Revision: 356571

URL: http://llvm.org/viewvc/llvm-project?rev=356571&view=rev
Log:
[OpenCL] Generate 'unroll.enable' metadata for  __attribute__((opencl_unroll_hint))

Summary:
[OpenCL] Generate 'unroll.enable' metadata for  __attribute__((opencl_unroll_hint))
    
For both !{!"llvm.loop.unroll.enable"} and !{!"llvm.loop.unroll.full"} the unroller
will try to fully unroll a loop unless the trip count is not known at compile time.
In that case for '.full' metadata no unrolling will be processed, while for '.enable'
the loop will be partially unrolled with a heuristically chosen unroll factor.
    
See: docs/LanguageExtensions.rst
    
>From https://www.khronos.org/registry/OpenCL/sdk/2.0/docs/man/xhtml/attributes-loopUnroll.html

    __attribute__((opencl_unroll_hint))
    for (int i=0; i<2; i++)
    {
        ...
    }
    
In the example above, the compiler will determine how much to unroll the loop.

    
Before the patch for  __attribute__((opencl_unroll_hint)) was generated metadata
!{!"llvm.loop.unroll.full"}, which limits ability of loop unroller to decide, how
much to unroll the loop.

Reviewers: Anastasia, yaxunl

Reviewed By: Anastasia

Subscribers: zzheng, dmgreen, jdoerfert, cfe-commits, asavonic, AlexeySotkin

Tags: #clang

Differential Revision: https://reviews.llvm.org/D59493

Modified:
    cfe/trunk/lib/CodeGen/CGLoopInfo.cpp
    cfe/trunk/test/CodeGenOpenCL/unroll-hint.cl

Modified: cfe/trunk/lib/CodeGen/CGLoopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGLoopInfo.cpp?rev=356571&r1=356570&r2=356571&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGLoopInfo.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGLoopInfo.cpp Wed Mar 20 09:43:07 2019
@@ -208,13 +208,13 @@ void LoopInfoStack::push(BasicBlock *Hea
     // Translate opencl_unroll_hint attribute argument to
     // equivalent LoopHintAttr enums.
     // OpenCL v2.0 s6.11.5:
-    // 0 - full unroll (no argument).
+    // 0 - enable unroll (no argument).
     // 1 - disable unroll.
     // other positive integer n - unroll by n.
     if (OpenCLHint) {
       ValueInt = OpenCLHint->getUnrollHint();
       if (ValueInt == 0) {
-        State = LoopHintAttr::Full;
+        State = LoopHintAttr::Enable;
       } else if (ValueInt != 1) {
         Option = LoopHintAttr::UnrollCount;
         State = LoopHintAttr::Numeric;

Modified: cfe/trunk/test/CodeGenOpenCL/unroll-hint.cl
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenOpenCL/unroll-hint.cl?rev=356571&r1=356570&r2=356571&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenOpenCL/unroll-hint.cl (original)
+++ cfe/trunk/test/CodeGenOpenCL/unroll-hint.cl Wed Mar 20 09:43:07 2019
@@ -18,12 +18,12 @@ void for_disable()
 // CHECK: br label %{{.*}}, !llvm.loop ![[FOR_DISABLE:.*]]
 }
 
-void for_full()
+void for_enable()
 {
-// CHECK-LABEL: for_full
+// CHECK-LABEL: for_enable
     __attribute__((opencl_unroll_hint))
     for( int i = 0; i < 1000; ++i);
-// CHECK: br label %{{.*}}, !llvm.loop ![[FOR_FULL:.*]]
+// CHECK: br label %{{.*}}, !llvm.loop ![[FOR_ENABLE:.*]]
 }
 
 /*** while ***/
@@ -45,13 +45,13 @@ void while_disable()
 // CHECK: br label %{{.*}}, !llvm.loop ![[WHILE_DISABLE:.*]]
 }
 
-void while_full()
+void while_enable()
 {
-// CHECK-LABEL: while_full
+// CHECK-LABEL: while_enable
     int i = 1000;
     __attribute__((opencl_unroll_hint))
     while(i-->0);
-// CHECK: br label %{{.*}}, !llvm.loop ![[WHILE_FULL:.*]]
+// CHECK: br label %{{.*}}, !llvm.loop ![[WHILE_ENABLE:.*]]
 }
 
 /*** do ***/
@@ -73,13 +73,13 @@ void do_disable()
 // CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}, !llvm.loop ![[DO_DISABLE:.*]]
 }
 
-void do_full()
+void do_enable()
 {
-// CHECK-LABEL: do_full
+// CHECK-LABEL: do_enable
     int i = 1000;
     __attribute__((opencl_unroll_hint))
     do {} while(i--> 0);
-// CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}, !llvm.loop ![[DO_FULL:.*]]
+// CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}, !llvm.loop ![[DO_ENABLE:.*]]
 }
 
 
@@ -87,11 +87,11 @@ void do_full()
 // CHECK: ![[COUNT]]         =  !{!"llvm.loop.unroll.count", i32 8}
 // CHECK: ![[FOR_DISABLE]]   =  distinct !{![[FOR_DISABLE]],  ![[DISABLE:.*]]}
 // CHECK: ![[DISABLE]]       =  !{!"llvm.loop.unroll.disable"}
-// CHECK: ![[FOR_FULL]]      =  distinct !{![[FOR_FULL]],  ![[FULL:.*]]}
-// CHECK: ![[FULL]]          =  !{!"llvm.loop.unroll.full"}
+// CHECK: ![[FOR_ENABLE]]      =  distinct !{![[FOR_ENABLE]],  ![[ENABLE:.*]]}
+// CHECK: ![[ENABLE]]          =  !{!"llvm.loop.unroll.enable"}
 // CHECK: ![[WHILE_COUNT]]   =  distinct !{![[WHILE_COUNT]],    ![[COUNT]]}
 // CHECK: ![[WHILE_DISABLE]] =  distinct !{![[WHILE_DISABLE]],  ![[DISABLE]]}
-// CHECK: ![[WHILE_FULL]]    =  distinct !{![[WHILE_FULL]],     ![[FULL]]}
+// CHECK: ![[WHILE_ENABLE]]    =  distinct !{![[WHILE_ENABLE]],     ![[ENABLE]]}
 // CHECK: ![[DO_COUNT]]      =  distinct !{![[DO_COUNT]],       ![[COUNT]]}
 // CHECK: ![[DO_DISABLE]]    =  distinct !{![[DO_DISABLE]],     ![[DISABLE]]}
-// CHECK: ![[DO_FULL]]       =  distinct !{![[DO_FULL]],        ![[FULL]]}
+// CHECK: ![[DO_ENABLE]]       =  distinct !{![[DO_ENABLE]],        ![[ENABLE]]}