Ignore annotation function calls in cost computation

The annotation instructions are dropped during codegen and have no
impact on size.  In some cases, the annotations were preventing the
unroller from unrolling a loop because the annotation calls were
pushing the cost over the unrolling threshold.

Differential Revision: http://reviews.llvm.org/D5335

llvm-svn: 218525

2 files changed, 134 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
index 9a0133a6c2b..e09babf1fbf 100644
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -392,6 +392,7 @@ struct NoTTI final : ImmutablePass, TargetTransformInfo {
       // FIXME: This is wrong for libc intrinsics.
       return TCC_Basic;
 
+    case Intrinsic::annotation:
     case Intrinsic::assume:
     case Intrinsic::dbg_declare:
     case Intrinsic::dbg_value:
diff --git a/llvm/test/Transforms/LoopUnroll/ignore-annotation-intrinsic-cost.ll b/llvm/test/Transforms/LoopUnroll/ignore-annotation-intrinsic-cost.ll
new file mode 100644
index 00000000000..dcb5d1c28fb
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnroll/ignore-annotation-intrinsic-cost.ll
@@ -0,0 +1,133 @@
+; REQUIRES: asserts
+; RUN: opt < %s -disable-output -stats -loop-unroll -info-output-file - | FileCheck %s --check-prefix=STATS
+; STATS: 1 loop-unroll - Number of loops unrolled (completely or otherwise)
+; Test that llvm.annotation intrinsic do not count against the loop body size
+; and prevent unrolling.
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-n32-S64"
+
+@B = common global i32 0, align 4
+
+define void @foo(i32* noalias %A, i32 %B, i32 %C) {
+entry:
+  br label %for.body
+
+; A loop that has a small loop body (except for the annotations) that should be
+; unrolled with the default heuristic. Make sure the extra annotations do not
+; prevent unrolling
+for.body:                                         ; preds = %entry, %for.body
+  %i.01 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  ; The real loop.
+  %mul = mul nsw i32 %B, %C
+  %arrayidx = getelementptr inbounds i32* %A, i32 %i.01
+  store i32 %mul, i32* %arrayidx, align 4
+  %inc = add nsw i32 %i.01, 1
+  %exitcond = icmp ne i32 %inc, 4
+
+  ; A bunch of annotations
+  %annot.0 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.1 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.2 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.3 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.4 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.5 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.6 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.7 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.8 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.9 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.10 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.11 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.12 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.13 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.14 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.15 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.16 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.17 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.18 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.19 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.20 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.21 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.22 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.23 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.24 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.25 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.26 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.27 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.28 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.29 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.30 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.31 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.32 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.33 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.34 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.35 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.36 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.37 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.38 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.39 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.40 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.41 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.42 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.43 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.44 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.45 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.46 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.47 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.48 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.49 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.50 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.51 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.52 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.53 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.54 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.55 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.56 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.57 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.58 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.59 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.60 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.61 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.62 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.63 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.64 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.65 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.66 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.67 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.68 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.69 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.70 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.71 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.72 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.73 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.74 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.75 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.76 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.77 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.78 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.79 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.80 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.81 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.82 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.83 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.84 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.85 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.86 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.87 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.88 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.89 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.90 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.91 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.92 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.93 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.94 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.95 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.96 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.97 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.98 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  %annot.99 = tail call i32 @llvm.annotation.i32(i32 %i.01, i8* null, i8* null, i32 0)
+  br i1 %exitcond, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body
+  ret void
+}
+
+declare i32 @llvm.annotation.i32(i32, i8*, i8*, i32)