Index: lib/Analysis/ScopInfo.cpp =================================================================== --- lib/Analysis/ScopInfo.cpp +++ lib/Analysis/ScopInfo.cpp @@ -1273,6 +1273,14 @@ for (MemoryAccess *MA : *Stmt) { if (MA->isScalar()) continue; + + // Skip accesses with an empty domain as they will never be executed. + isl_set *MADomain = MA->getStatement()->getDomain(); + bool MADomainEmpty = isl_set_is_empty(MADomain); + isl_set_free(MADomain); + if (MADomainEmpty) + continue; + if (!MA->isRead()) HasWriteAccess.insert(MA->getBaseAddr()); Instruction *Acc = MA->getAccessInstruction(); Index: test/ScopInfo/aliasing_dead_access.ll =================================================================== --- /dev/null +++ test/ScopInfo/aliasing_dead_access.ll @@ -0,0 +1,53 @@ +; RUN: opt %loadPolly -polly-codegen-scev -polly-code-generator=isl -analyze -polly-scops < %s | FileCheck %s +; +; Check that RTC generation does not die when accesses are dead. +; +; CHECK: Alias Groups (0): +; +; void jd(int *A, int *B) { +; for (int i = 0; i < 1024; i++) +; for (int j = i; j < 0; j++) +; A[i] = B[i]; +; } +; +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" + +define void @jd(i32* %A, i32* %B) { +entry: + br label %for.cond + +for.cond: ; preds = %for.inc6, %entry + %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc6 ], [ 0, %entry ] + %exitcond = icmp ne i64 %indvars.iv, 1024 + br i1 %exitcond, label %for.body, label %for.end8 + +for.body: ; preds = %for.cond + %tmp = trunc i64 %indvars.iv to i32 + br label %for.cond1 + +for.cond1: ; preds = %for.inc, %for.body + %j.0 = phi i32 [ %tmp, %for.body ], [ %inc, %for.inc ] + %cmp2 = icmp slt i32 %j.0, 0 + br i1 %cmp2, label %for.body3, label %for.end + +for.body3: ; preds = %for.cond1 + %arrayidx = getelementptr inbounds i32* %B, i64 %indvars.iv + %tmp1 = load i32* %arrayidx, align 4 + %arrayidx5 = getelementptr inbounds i32* %A, i64 %indvars.iv + store i32 %tmp1, i32* %arrayidx5, align 4 + br label %for.inc + +for.inc: ; preds = %for.body3 + %inc = add nsw i32 %j.0, 1 + br label %for.cond1 + +for.end: ; preds = %for.cond1 + br label %for.inc6 + +for.inc6: ; preds = %for.end + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 + br label %for.cond + +for.end8: ; preds = %for.cond + ret void +}