Don't check side effects for functions outside of SCoP

Eli Friedman · Eli Friedman · commit 127e0cd21b6e · 2017-06-14T22:43:28.000Z
In r304074 we introduce a patch to accept results from side effect free
functions into SCEV modeling. This causes rejection of cases where the
call is happening outside the SCoP. This patch checks if the call is
outside the Region and treats the results as a parameter (SCEVType::PARAM)
to the SCoP instead of returning SCEVType::INVALID.

Patch by Sameer Abu Asal.

llvm-svn: 305423
diff --git a/polly/lib/Support/SCEVValidator.cpp b/polly/lib/Support/SCEVValidator.cpp
@@ -320,11 +320,12 @@ struct SCEVValidator
   ValidatorResult visitCallInstruction(Instruction *I, const SCEV *S) {
     assert(I->getOpcode() == Instruction::Call && "Call instruction expected");
 
-    auto Call = cast<CallInst>(I);
-
-    if (!isConstCall(Call))
-      return ValidatorResult(SCEVType::INVALID, S);
+    if (R->contains(I)) {
+      auto Call = cast<CallInst>(I);
 
+      if (!isConstCall(Call))
+        return ValidatorResult(SCEVType::INVALID, S);
+    }
     return ValidatorResult(SCEVType::PARAM, S);
   }
 
diff --git a/polly/test/ScopInfo/constant_functions_outside_scop_as_unknown.ll b/polly/test/ScopInfo/constant_functions_outside_scop_as_unknown.ll
@@ -0,0 +1,36 @@
+; RUN: opt -polly-process-unprofitable -polly-scops -analyze < %s | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
+
+; CHECK: Region: %for.cond62---%for.cond
+; CHECK: p0: {0,+,1}<nuw><%for.cond>
+; CHECK-NEXT: p1: %param1
+; CHECK-NEXT: p2: %param2
+; CHECK-NEXT: Arrays {
+
+define void @f(i8* %param1) {
+entry:
+  br label %for.cond
+
+for.cond:
+  %hook = phi i8* [ %param1, %entry ], [ %add.ptr201, %cleanup ]
+  br i1 undef, label %for.body, label %for.cond.cleanup
+
+for.body:
+  %param2 = call i32 @g()
+  %add.ptr60 = getelementptr inbounds i8, i8* %hook, i32 %param2
+  br label %for.cond62
+
+for.cond62:
+  %cmp64 = icmp ule i8* %add.ptr60, null
+  br i1 %cmp64, label %for.cond62, label %cleanup
+
+cleanup:
+  %add.ptr201 = getelementptr inbounds i8, i8* %hook, i32 1
+  br label %for.cond
+
+for.cond.cleanup:
+  ret void
+}
+
+declare i32 @g()
