diff --git a/llvm/test/Transforms/LoopInterchange/ninf.ll b/llvm/test/Transforms/LoopInterchange/ninf.ll new file mode 100644 index 0000000000000..896c8467efdc0 --- /dev/null +++ b/llvm/test/Transforms/LoopInterchange/ninf.ll @@ -0,0 +1,154 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6 +; RUN: opt < %s -passes=loop-interchange -loop-interchange-profitabilities=ignore -S | FileCheck %s + +; sum = 0.0; +; for (i = 0; i < 2; i++) +; for (j = 0; j < 2; j++) +; sum += A[i][j]; +; +; The fadd instruction has reassoc flag, so it's legal to interchange the +; loops. However, it also has ninf flag, which means the transformation +; potentially produces a poison due to the change of the order of evaluation. +; For example, consider the case where +; A[2][2] = {{FLT_MAX, -FLT_MAX}, {FLT_MAX, -FLT_MAX}}. +; +; FIXME: The ninf flag should be dropped when the loop interchange is applied. +; +define noundef float @reduction_reassoc_ninf(ptr %A) { +; CHECK-LABEL: define noundef float @reduction_reassoc_ninf( +; CHECK-SAME: ptr [[A:%.*]]) { +; CHECK-NEXT: [[ENTRY:.*:]] +; CHECK-NEXT: br label %[[FOR_J_PREHEADER:.*]] +; CHECK: [[FOR_I_HEADER_PREHEADER:.*]]: +; CHECK-NEXT: br label %[[FOR_I_HEADER:.*]] +; CHECK: [[FOR_I_HEADER]]: +; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_INC:%.*]], %[[FOR_I_LATCH:.*]] ], [ 0, %[[FOR_I_HEADER_PREHEADER]] ] +; CHECK-NEXT: [[SUM_J:%.*]] = phi float [ [[SUM_J_NEXT:%.*]], %[[FOR_I_LATCH]] ], [ [[SUM_I:%.*]], %[[FOR_I_HEADER_PREHEADER]] ] +; CHECK-NEXT: br label %[[FOR_J_SPLIT1:.*]] +; CHECK: [[FOR_J_PREHEADER]]: +; CHECK-NEXT: br label %[[FOR_J:.*]] +; CHECK: [[FOR_J]]: +; CHECK-NEXT: [[J:%.*]] = phi i64 [ [[TMP0:%.*]], %[[FOR_J_SPLIT:.*]] ], [ 0, %[[FOR_J_PREHEADER]] ] +; CHECK-NEXT: [[SUM_I]] = phi float [ [[SUM_I_NEXT:%.*]], %[[FOR_J_SPLIT]] ], [ 0.000000e+00, %[[FOR_J_PREHEADER]] ] +; CHECK-NEXT: br label %[[FOR_I_HEADER_PREHEADER]] +; CHECK: [[FOR_J_SPLIT1]]: +; CHECK-NEXT: [[GEP:%.*]] = getelementptr [2 x float], ptr [[A]], i64 [[I]], i64 [[J]] +; CHECK-NEXT: [[VAL:%.*]] = load float, ptr [[GEP]], align 4 +; CHECK-NEXT: [[SUM_J_NEXT]] = fadd reassoc ninf float [[SUM_J]], [[VAL]] +; CHECK-NEXT: [[J_INC:%.*]] = add i64 [[J]], 1 +; CHECK-NEXT: [[EC_J:%.*]] = icmp eq i64 [[J_INC]], 2 +; CHECK-NEXT: br label %[[FOR_I_LATCH]] +; CHECK: [[FOR_J_SPLIT]]: +; CHECK-NEXT: [[SUM_I_NEXT]] = phi float [ [[SUM_J_NEXT]], %[[FOR_I_LATCH]] ] +; CHECK-NEXT: [[TMP0]] = add i64 [[J]], 1 +; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[TMP0]], 2 +; CHECK-NEXT: br i1 [[TMP1]], label %[[EXIT:.*]], label %[[FOR_J]] +; CHECK: [[FOR_I_LATCH]]: +; CHECK-NEXT: [[I_INC]] = add i64 [[I]], 1 +; CHECK-NEXT: [[EC_I:%.*]] = icmp eq i64 [[I_INC]], 2 +; CHECK-NEXT: br i1 [[EC_I]], label %[[FOR_J_SPLIT]], label %[[FOR_I_HEADER]] +; CHECK: [[EXIT]]: +; CHECK-NEXT: [[SUM_I_NEXT_LCSSA:%.*]] = phi float [ [[SUM_I_NEXT]], %[[FOR_J_SPLIT]] ] +; CHECK-NEXT: ret float [[SUM_I_NEXT_LCSSA]] +; +entry: + br label %for.i.header + +for.i.header: + %i = phi i64 [ 0, %entry ], [ %i.inc, %for.i.latch ] + %sum.i = phi float [ 0.0, %entry ], [ %sum.i.next, %for.i.latch ] + br label %for.j + +for.j: + %j = phi i64 [ 0, %for.i.header ], [ %j.inc, %for.j ] + %sum.j = phi float [ %sum.i, %for.i.header ], [ %sum.j.next, %for.j ] + %gep = getelementptr [2 x float], ptr %A, i64 %i, i64 %j + %val = load float, ptr %gep + %sum.j.next = fadd reassoc ninf float %sum.j, %val + %j.inc = add i64 %j, 1 + %ec.j = icmp eq i64 %j.inc, 2 + br i1 %ec.j, label %for.i.latch, label %for.j + +for.i.latch: + %sum.i.next = phi float [ %sum.j.next, %for.j ] + %i.inc = add i64 %i, 1 + %ec.i = icmp eq i64 %i.inc, 2 + br i1 %ec.i, label %exit, label %for.i.header + +exit: + ret float %sum.i.next +} + +; for (i = 0; i < 2; i++) +; for (j = 0; j < 2; j++) +; C[i][j] = A[i][j] + B[i][j]; +; +; The fadd instruction has ninf flag, but different from the above example, +; it's not a reduction so interchanging the loops shouldn't result in a poison +; value. +; +define void @non_reduction_ninf(ptr %A, ptr %B, ptr noalias %C) { +; CHECK-LABEL: define void @non_reduction_ninf( +; CHECK-SAME: ptr [[A:%.*]], ptr [[B:%.*]], ptr noalias [[C:%.*]]) { +; CHECK-NEXT: [[ENTRY:.*:]] +; CHECK-NEXT: br label %[[FOR_J_PREHEADER:.*]] +; CHECK: [[FOR_I_HEADER_PREHEADER:.*]]: +; CHECK-NEXT: br label %[[FOR_I_HEADER:.*]] +; CHECK: [[FOR_I_HEADER]]: +; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_INC:%.*]], %[[FOR_I_LATCH:.*]] ], [ 0, %[[FOR_I_HEADER_PREHEADER]] ] +; CHECK-NEXT: br label %[[FOR_J_SPLIT1:.*]] +; CHECK: [[FOR_J_PREHEADER]]: +; CHECK-NEXT: br label %[[FOR_J:.*]] +; CHECK: [[FOR_J]]: +; CHECK-NEXT: [[J:%.*]] = phi i64 [ [[TMP0:%.*]], %[[FOR_J_SPLIT:.*]] ], [ 0, %[[FOR_J_PREHEADER]] ] +; CHECK-NEXT: br label %[[FOR_I_HEADER_PREHEADER]] +; CHECK: [[FOR_J_SPLIT1]]: +; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr [2 x float], ptr [[A]], i64 [[I]], i64 [[J]] +; CHECK-NEXT: [[VAL_A:%.*]] = load float, ptr [[GEP_A]], align 4 +; CHECK-NEXT: [[GEP_B:%.*]] = getelementptr [2 x float], ptr [[B]], i64 [[I]], i64 [[J]] +; CHECK-NEXT: [[VAL_B:%.*]] = load float, ptr [[GEP_B]], align 4 +; CHECK-NEXT: [[SUM:%.*]] = fadd ninf float [[VAL_A]], [[VAL_B]] +; CHECK-NEXT: [[GEP_C:%.*]] = getelementptr [2 x float], ptr [[C]], i64 [[I]], i64 [[J]] +; CHECK-NEXT: store float [[SUM]], ptr [[GEP_C]], align 4 +; CHECK-NEXT: [[J_INC:%.*]] = add i64 [[J]], 1 +; CHECK-NEXT: [[EC_J:%.*]] = icmp eq i64 [[J_INC]], 2 +; CHECK-NEXT: br label %[[FOR_I_LATCH]] +; CHECK: [[FOR_J_SPLIT]]: +; CHECK-NEXT: [[TMP0]] = add i64 [[J]], 1 +; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[TMP0]], 2 +; CHECK-NEXT: br i1 [[TMP1]], label %[[EXIT:.*]], label %[[FOR_J]] +; CHECK: [[FOR_I_LATCH]]: +; CHECK-NEXT: [[I_INC]] = add i64 [[I]], 1 +; CHECK-NEXT: [[EC_I:%.*]] = icmp eq i64 [[I_INC]], 2 +; CHECK-NEXT: br i1 [[EC_I]], label %[[FOR_J_SPLIT]], label %[[FOR_I_HEADER]] +; CHECK: [[EXIT]]: +; CHECK-NEXT: ret void +; +entry: + br label %for.i.header + +for.i.header: + %i = phi i64 [ 0, %entry ], [ %i.inc, %for.i.latch ] + br label %for.j + +for.j: + %j = phi i64 [ 0, %for.i.header ], [ %j.inc, %for.j ] + %gep.A = getelementptr [2 x float], ptr %A, i64 %i, i64 %j + %val.A = load float, ptr %gep.A + %gep.B = getelementptr [2 x float], ptr %B, i64 %i, i64 %j + %val.B = load float, ptr %gep.B + %sum = fadd ninf float %val.A, %val.B + %gep.C = getelementptr [2 x float], ptr %C, i64 %i, i64 %j + store float %sum, ptr %gep.C + %j.inc = add i64 %j, 1 + %ec.j = icmp eq i64 %j.inc, 2 + br i1 %ec.j, label %for.i.latch, label %for.j + +for.i.latch: + %i.inc = add i64 %i, 1 + %ec.i = icmp eq i64 %i.inc, 2 + br i1 %ec.i, label %exit, label %for.i.header + +exit: + ret void +}