; RUN: opt %loadPolly -polly-delicm -analyze < %s | FileCheck %s ; ; void func(double *A) { ; for (int j = 0; j < 2; j += 1) { /* outer */ ; double phi = 0.0; ; for (int i = 0; i < 4; i += 1) /* reduction */ ; if (phi < 0.0) ; A[j] = undef; ; phi += 4.2; ; A[j] = phi; ; } ; } ; ; The MAY_WRITE in reduction.for.true conflict with a write of %phi to ; A[j] if %phi would be mapped to it. Being a MAY_WRITE avoids being target ; of a mapping itself. ; ; TODO: There is actually no reason why these conflict. The MAY_WRITE is an ; explicit write, defined to occur always before all implicit writes as the ; write of %phi would be. There is currently no differentiation between ; implicit and explicit writes in Polly. ; define void @func(double* noalias nonnull %A) { entry: %fsomeval = fadd double 21.0, 21.0 br label %outer.preheader outer.preheader: br label %outer.for outer.for: %j = phi i32 [0, %outer.preheader], [%j.inc, %outer.inc] %j.cmp = icmp slt i32 %j, 2 br i1 %j.cmp, label %reduction.preheader, label %outer.exit reduction.preheader: br label %reduction.for reduction.for: %i = phi i32 [0, %reduction.preheader], [%i.inc, %reduction.inc] %phi = phi double [0.0, %reduction.preheader], [%add, %reduction.inc] %A_idx = getelementptr inbounds double, double* %A, i32 %j %phi.cmp = fcmp ogt double %phi, 0.0 br i1 %phi.cmp, label %reduction.for.true, label %reduction.for.unconditional reduction.for.true: store double undef, double* %A_idx br label %reduction.for.unconditional reduction.for.unconditional: %i.cmp = icmp slt i32 %i, 4 br i1 %i.cmp, label %body, label %reduction.exit body: %add = fadd double %phi, 4.2 br label %reduction.inc reduction.inc: %i.inc = add nuw nsw i32 %i, 1 br label %reduction.for reduction.exit: store double %phi, double* %A_idx br label %outer.inc outer.inc: %j.inc = add nuw nsw i32 %j, 1 br label %outer.for outer.exit: br label %return return: ret void } ; CHECK: Statistics { ; CHECK: Compatible overwrites: 1 ; CHECK: } ; CHECK: No modification has been made