diff --git a/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll b/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll @@ -0,0 +1,388 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt -S -instcombine < %s | FileCheck %s + +; Check if a value can be deduced as a power of 2, allowing urem optimization. +; i.e. A urem B = A & (B - 1) if B is a power of 2. + +define i64 @known_power_of_two_urem_phi(i64 %size, i1 %cmp, i1 %cmp1) { +; CHECK-LABEL: @known_power_of_two_urem_phi( +; CHECK-NEXT: entry: +; CHECK-NEXT: br i1 [[CMP:%.*]], label [[COND_TRUE:%.*]], label [[COND_END:%.*]] +; CHECK: cond.true: +; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[COND_TRUE_TRUE:%.*]], label [[COND_TRUE_FALSE:%.*]] +; CHECK: cond.true.true: +; CHECK-NEXT: br label [[COND_TRUE_END:%.*]] +; CHECK: cond.true.false: +; CHECK-NEXT: br label [[COND_TRUE_END]] +; CHECK: cond.true.end: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 2, [[COND_TRUE_TRUE]] ], [ 4, [[COND_TRUE_FALSE]] ] +; CHECK-NEXT: br label [[COND_END]] +; CHECK: cond.end: +; CHECK-NEXT: [[PHI1:%.*]] = phi i64 [ 4096, [[ENTRY:%.*]] ], [ [[PHI]], [[COND_TRUE_END]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI1]] +; CHECK-NEXT: ret i64 [[UREM]] +; +entry: + br i1 %cmp, label %cond.true, label %cond.end + +cond.true: + br i1 %cmp1, label %cond.true.true, label %cond.true.false + +cond.true.true: + br label %cond.true.end + +cond.true.false: + br label %cond.true.end + +cond.true.end: + %phi = phi i64 [ 2, %cond.true.true ], [ 4, %cond.true.false ] + br label %cond.end + +cond.end: + %phi1 = phi i64 [ 4096, %entry ], [ %phi, %cond.true.end ] + %urem = urem i64 %size, %phi1 + ret i64 %urem +} + +define i64 @known_power_of_two_urem_nested_expr(i64 %size, i1 %cmp, i1 %cmp1, i64 %0) { +; CHECK-LABEL: @known_power_of_two_urem_nested_expr( +; CHECK-NEXT: entry: +; CHECK-NEXT: br i1 [[CMP:%.*]], label [[COND_TRUE:%.*]], label [[COND_FALSE:%.*]] +; CHECK: cond.true: +; CHECK-NEXT: [[TMP1:%.*]] = shl nuw i64 1, [[TMP0:%.*]] +; CHECK-NEXT: br label [[COND_END:%.*]] +; CHECK: cond.false: +; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[CMP1:%.*]], i64 2, i64 8 +; CHECK-NEXT: br label [[COND_END]] +; CHECK: cond.end: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[SELECT]], [[COND_FALSE]] ], [ [[TMP1]], [[COND_TRUE]] ], [ [[PHI]], [[COND_END]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i64 [[UREM]], 10 +; CHECK-NEXT: br i1 [[CMP2]], label [[COND_END]], label [[END:%.*]] +; CHECK: end: +; CHECK-NEXT: ret i64 [[UREM]] +; +entry: + br i1 %cmp, label %cond.true, label %cond.false + +cond.true: + %1 = shl nuw i64 1, %0 + br label %cond.end + +cond.false: + %select = select i1 %cmp1, i64 2, i64 8 + br label %cond.end + +cond.end: + %phi = phi i64 [ %select, %cond.false ], [ %1, %cond.true ], [ %phi, %cond.end ] + %2 = phi i64 [ %size, %cond.false ], [ %size, %cond.true ], [ %0, %cond.end ] + %urem = urem i64 %size, %phi + %cmp2 = icmp ult i64 %urem, 10 + br i1 %cmp2, label %cond.end, label %end + +end: + ret i64 %urem +} + +define i64 @known_power_of_two_urem_negative(i64 %size, i1 %cmp, i64 %0) { +; urem is not replaced if not all operands are power of 2. +; +; CHECK-LABEL: @known_power_of_two_urem_negative( +; CHECK-NEXT: entry: +; CHECK-NEXT: br i1 [[CMP:%.*]], label [[COND_TRUE:%.*]], label [[COND_END:%.*]] +; CHECK: cond.true: +; CHECK-NEXT: br label [[COND_END]] +; CHECK: cond.end: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 4, [[ENTRY:%.*]] ], [ [[TMP0:%.*]], [[COND_TRUE]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: ret i64 [[UREM]] +; +entry: + br i1 %cmp, label %cond.true, label %cond.end + +cond.true: + br label %cond.end + +cond.end: + %phi = phi i64 [ 4, %entry ], [ %0, %cond.true ] + %urem = urem i64 %size, %phi + ret i64 %urem +} + +define i64 @known_power_of_two_urem_loop_mul(i64 %size, i64 %a) { +; CHECK-LABEL: @known_power_of_two_urem_loop_mul( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]] +; CHECK-NEXT: br label [[FOR_BODY:%.*]] +; CHECK: for.body: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]] +; CHECK-NEXT: [[I]] = shl nuw i64 [[PHI]], 2 +; CHECK-NEXT: [[ICMP:%.*]] = icmp ult i64 [[PHI]], 25000000 +; CHECK-NEXT: br i1 [[ICMP]], label [[FOR_BODY]], label [[FOR_END:%.*]] +; CHECK: for.end: +; CHECK-NEXT: ret i64 [[SUM]] +; +entry: + %start = shl nuw i64 1, %a + br label %for.body + +for.body: + %phi = phi i64 [ %start, %entry ], [ %i, %for.body ] + %sum = phi i64 [ 0, %entry ], [ %add, %for.body ] + %urem = urem i64 %size, %phi + %add = add nuw i64 %sum, %urem + %i = mul nuw i64 %phi, 4 + %icmp = icmp ult i64 %i, 100000000 + br i1 %icmp, label %for.body, label %for.end + +for.end: + %r = phi i64 [ %sum, %for.body ] + ret i64 %r +} + +define i64 @known_power_of_two_urem_loop_mul_negative(i64 %size, i64 %a) { +; Cannot deduce induction variable is a power of 2 if it is multiplied by 3. +; +; CHECK-LABEL: @known_power_of_two_urem_loop_mul_negative( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]] +; CHECK-NEXT: br label [[FOR_BODY:%.*]] +; CHECK: for.body: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]] +; CHECK-NEXT: [[I]] = mul nuw i64 [[PHI]], 3 +; CHECK-NEXT: [[ICMP:%.*]] = icmp ult i64 [[I]], 100000000 +; CHECK-NEXT: br i1 [[ICMP]], label [[FOR_BODY]], label [[FOR_END:%.*]] +; CHECK: for.end: +; CHECK-NEXT: ret i64 [[SUM]] +; +entry: + %start = shl nuw i64 1, %a + br label %for.body + +for.body: + %phi = phi i64 [ %start, %entry ], [ %i, %for.body ] + %sum = phi i64 [ 0, %entry ], [ %add, %for.body ] + %urem = urem i64 %size, %phi + %add = add nuw i64 %sum, %urem + %i = mul nuw i64 %phi, 3 + %icmp = icmp ult i64 %i, 100000000 + br i1 %icmp, label %for.body, label %for.end + +for.end: + %r = phi i64 [ %sum, %for.body ] + ret i64 %r +} + +define i64 @known_power_of_two_urem_loop_shl(i64 %size, i64 %a) { +; CHECK-LABEL: @known_power_of_two_urem_loop_shl( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]] +; CHECK-NEXT: br label [[FOR_BODY:%.*]] +; CHECK: for.body: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]] +; CHECK-NEXT: [[I]] = shl nuw i64 [[PHI]], 1 +; CHECK-NEXT: [[ICMP:%.*]] = icmp ult i64 [[PHI]], 50000000 +; CHECK-NEXT: br i1 [[ICMP]], label [[FOR_BODY]], label [[FOR_END:%.*]] +; CHECK: for.end: +; CHECK-NEXT: ret i64 [[SUM]] +; +entry: + %start = shl nuw i64 1, %a + br label %for.body + +for.body: + %phi = phi i64 [ %start, %entry ], [ %i, %for.body ] + %sum = phi i64 [ 0, %entry ], [ %add, %for.body ] + %urem = urem i64 %size, %phi + %add = add nuw i64 %sum, %urem + %i = shl nuw i64 %phi, 1 + %icmp = icmp ult i64 %i, 100000000 + br i1 %icmp, label %for.body, label %for.end + +for.end: + %r = phi i64 [ %sum, %for.body ] + ret i64 %r +} + +define i64 @known_power_of_two_urem_loop_lshr(i64 %size, i64 %a) { +; CHECK-LABEL: @known_power_of_two_urem_loop_lshr( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]] +; CHECK-NEXT: br label [[FOR_BODY:%.*]] +; CHECK: for.body: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]] +; CHECK-NEXT: [[I]] = lshr i64 [[PHI]], 1 +; CHECK-NEXT: [[ICMP_NOT:%.*]] = icmp ult i64 [[PHI]], 2 +; CHECK-NEXT: br i1 [[ICMP_NOT]], label [[FOR_END:%.*]], label [[FOR_BODY]] +; CHECK: for.end: +; CHECK-NEXT: ret i64 [[SUM]] +; +entry: + %start = shl nuw i64 1, %a + br label %for.body + +for.body: + %phi = phi i64 [ %start, %entry ], [ %i, %for.body ] + %sum = phi i64 [ 0, %entry ], [ %add, %for.body ] + %urem = urem i64 %size, %phi + %add = add nuw i64 %sum, %urem + %i = lshr i64 %phi, 1 + %icmp = icmp ugt i64 %i, 0 + br i1 %icmp, label %for.body, label %for.end + +for.end: + %r = phi i64 [ %sum, %for.body ] + ret i64 %r +} + + +define i64 @known_power_of_two_urem_loop_ashr(i64 %size, i64 %a) { +; CHECK-LABEL: @known_power_of_two_urem_loop_ashr( +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[FOR_BODY:%.*]] +; CHECK: for.body: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 4096, [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[ADD]] = add nuw nsw i64 [[SUM]], [[UREM]] +; CHECK-NEXT: [[I]] = lshr i64 [[PHI]], [[A:%.*]] +; CHECK-NEXT: [[ICMP_NOT:%.*]] = icmp eq i64 [[I]], 0 +; CHECK-NEXT: br i1 [[ICMP_NOT]], label [[FOR_END:%.*]], label [[FOR_BODY]] +; CHECK: for.end: +; CHECK-NEXT: ret i64 [[SUM]] +; +entry: + br label %for.body + +for.body: + %phi = phi i64 [ 4096, %entry ], [ %i, %for.body ] + %sum = phi i64 [ 0, %entry ], [ %add, %for.body ] + %urem = urem i64 %size, %phi + %add = add nsw i64 %sum, %urem + %i = ashr i64 %phi, %a + %icmp = icmp ugt i64 %i, 0 + br i1 %icmp, label %for.body, label %for.end + +for.end: + %r = phi i64 [ %sum, %for.body ] + ret i64 %r +} + +define i64 @known_power_of_two_urem_loop_ashr_negative(i64 %size, i64 %a) { +; Cannot deduce induction variable is a power of 2 for ashr if its starting +; value is equal to sign bit +; +; CHECK-LABEL: @known_power_of_two_urem_loop_ashr_negative( +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[FOR_BODY:%.*]] +; CHECK: for.body: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ -9223372036854775808, [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[ADD]] = add nsw i64 [[SUM]], [[UREM]] +; CHECK-NEXT: [[I]] = ashr i64 [[PHI]], [[A:%.*]] +; CHECK-NEXT: br i1 true, label [[FOR_BODY]], label [[FOR_END:%.*]] +; CHECK: for.end: +; CHECK-NEXT: ret i64 [[SUM]] +; +entry: + br label %for.body + +for.body: + %phi = phi i64 [ u0x8000000000000000, %entry ], [ %i, %for.body ] + %sum = phi i64 [ 0, %entry ], [ %add, %for.body ] + %urem = urem i64 %size, %phi + %add = add nsw i64 %sum, %urem + %i = ashr i64 %phi, %a + %icmp = icmp ugt i64 %i, 0 + br i1 %icmp, label %for.body, label %for.end + +for.end: + %r = phi i64 [ %sum, %for.body ] + ret i64 %r +} + +define i64 @known_power_of_two_urem_loop_ashr_negative_2(i64 %size, i64 %a) { +; Cannot deduce induction variable is a power of 2 for ashr if its starting +; value may equal to sign bit. +; +; CHECK-LABEL: @known_power_of_two_urem_loop_ashr_negative_2( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]] +; CHECK-NEXT: br label [[FOR_BODY:%.*]] +; CHECK: for.body: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[ADD]] = add nsw i64 [[SUM]], [[UREM]] +; CHECK-NEXT: [[I]] = ashr i64 [[PHI]], 2 +; CHECK-NEXT: [[ICMP_NOT:%.*]] = icmp ult i64 [[PHI]], 4 +; CHECK-NEXT: br i1 [[ICMP_NOT]], label [[FOR_END:%.*]], label [[FOR_BODY]] +; CHECK: for.end: +; CHECK-NEXT: ret i64 [[SUM]] +; +entry: + %start = shl nuw i64 1, %a + br label %for.body + +for.body: + %phi = phi i64 [ %start, %entry ], [ %i, %for.body ] + %sum = phi i64 [ 0, %entry ], [ %add, %for.body ] + %urem = urem i64 %size, %phi + %add = add nsw i64 %sum, %urem + %i = ashr i64 %phi, 2 + %icmp = icmp ugt i64 %i, 0 + br i1 %icmp, label %for.body, label %for.end + +for.end: + %r = phi i64 [ %sum, %for.body ] + ret i64 %r +} + +define i64 @known_power_of_two_urem_loop_negative(i64 %size, i64 %a) { +; Cannot deduce induction variable is a power of 2 if the recurrence is not one +; of the valid arithmetic operations. +; +; CHECK-LABEL: @known_power_of_two_urem_loop_negative( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]] +; CHECK-NEXT: br label [[FOR_BODY:%.*]] +; CHECK: for.body: +; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ] +; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]] +; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]] +; CHECK-NEXT: [[I]] = add nuw i64 [[PHI]], 1 +; CHECK-NEXT: br i1 true, label [[FOR_BODY]], label [[FOR_END:%.*]] +; CHECK: for.end: +; CHECK-NEXT: ret i64 [[SUM]] +; +entry: + %start = shl nuw i64 1, %a + br label %for.body + +for.body: + %phi = phi i64 [ %start, %entry ], [ %i, %for.body ] + %sum = phi i64 [ 0, %entry ], [ %add, %for.body ] + %urem = urem i64 %size, %phi + %add = add nuw i64 %sum, %urem + %i = add nuw i64 %phi, 1 + %icmp = icmp ugt i64 %i, 0 + br i1 %icmp, label %for.body, label %for.end + +for.end: + %r = phi i64 [ %sum, %for.body ] + ret i64 %r +}