[llvm] r191122 - LoopVectorizer: Only allow vectorization of intrinsics. We can't know for sure that the functions 'abs' or 'round' are the functions from libm.

[Nadav Rotem]

Author: nadav
Date: Fri Sep 20 19:27:05 2013
New Revision: 191122

URL: http://llvm.org/viewvc/llvm-project?rev=191122&view=rev
Log:
LoopVectorizer: Only allow vectorization of intrinsics. We can't know for sure that the functions 'abs' or 'round' are the functions from libm.

rdar://15012650


Modified:
    llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
    llvm/trunk/test/Transforms/LoopVectorize/intrinsic.ll

Modified: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=191122&r1=191121&r2=191122&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp Fri Sep 20 19:27:05 2013
@@ -2925,9 +2925,18 @@ bool LoopVectorizationLegality::canVecto
       // We still don't handle functions. However, we can ignore dbg intrinsic
       // calls and we do handle certain intrinsic and libm functions.
       CallInst *CI = dyn_cast<CallInst>(it);
-      if (CI && !getIntrinsicIDForCall(CI, TLI) && !isa<DbgInfoIntrinsic>(CI)) {
+      if (CI) {
         DEBUG(dbgs() << "LV: Found a call site.\n");
-        return false;
+
+        if (!isa<IntrinsicInst>(it)) {
+          DEBUG(dbgs() << "LV: We only vectorize intrinsics.\n");
+          return false;
+        }
+
+        if (!getIntrinsicIDForCall(CI, TLI) && !isa<DbgInfoIntrinsic>(CI)) {
+          DEBUG(dbgs() << "LV: Found an unknown intrinsic.\n");
+          return false;
+        }
       }
 
       // Check that the instruction return type is vectorizable.

Modified: llvm/trunk/test/Transforms/LoopVectorize/intrinsic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/intrinsic.ll?rev=191122&r1=191121&r2=191122&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/intrinsic.ll (original)
+++ llvm/trunk/test/Transforms/LoopVectorize/intrinsic.ll Fri Sep 20 19:27:05 2013
@@ -1018,7 +1018,7 @@ for.body:
   %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
   %arrayidx = getelementptr inbounds float* %x, i64 %indvars.iv
   %0 = load float* %arrayidx, align 4
-  %call = tail call float @fabsf(float %0) nounwind readnone
+  %call = tail call float @llvm.fabs.f32(float %0) nounwind readnone
   store float %call, float* %arrayidx, align 4
   %indvars.iv.next = add i64 %indvars.iv, 1
   %lftr.wideiv = trunc i64 %indvars.iv.next to i32
@@ -1029,6 +1029,31 @@ for.end:
   ret void
 }
 
-declare float @fabsf(float) nounwind readnone
-
 declare double @llvm.pow.f64(double, double) nounwind readnone
+
+
+;CHECK: @not_intrin
+;CHECK: @round
+;CHECK-NOT: @round
+;CHECK: ret
+define void @not_intrin(i32* nocapture %A) nounwind ssp uwtable {
+  br label %1
+
+; <label>:1                                       ; preds = %1, %0
+  %indvars.iv = phi i64 [ 0, %0 ], [ %indvars.iv.next, %1 ]
+  %2 = getelementptr inbounds i32* %A, i64 %indvars.iv
+  %3 = load i32* %2, align 4
+  %4 = add nsw i32 %3, 3
+  store i32 %4, i32* %2, align 4
+  %5 = trunc i64 %indvars.iv to i32
+  tail call void @round(i32 %5) nounwind
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, 256
+  br i1 %exitcond, label %6, label %1
+
+; <label>:6                                       ; preds = %1
+  ret void
+}
+
+declare void @round(i32)