Fixing peelFirstIteration. Was incorrectly replacing all ub inside peeled iteration region. #163720
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@llvm/pr-subscribers-mlir-scf Author: None (ddubov100) ChangesCurrently when peeling first iteration - any mention of ub within the loop body is replaced with new ub in peeled out first iteration. Another thing is that this implementation is opposite to how peel_last works. I added test which presents this: static_two_terations_ub_used_in_loop, which I added to both front and last lit tests files. I added comments within the lit tests which explain why current implementation is correct and previous cause bugs. Full diff: https://github.com/llvm/llvm-project/pull/163720.diff 3 Files Affected:
diff --git a/mlir/lib/Dialect/SCF/Transforms/LoopSpecialization.cpp b/mlir/lib/Dialect/SCF/Transforms/LoopSpecialization.cpp
index e3717aa9d940e..43fbcbae7791b 100644
--- a/mlir/lib/Dialect/SCF/Transforms/LoopSpecialization.cpp
+++ b/mlir/lib/Dialect/SCF/Transforms/LoopSpecialization.cpp
@@ -241,9 +241,10 @@ LogicalResult mlir::scf::peelForLoopFirstIteration(RewriterBase &b, ForOp forOp,
// Peel the first iteration.
IRMapping map;
- map.map(forOp.getUpperBound(), splitBound);
firstIteration = cast<ForOp>(b.clone(*forOp.getOperation(), map));
-
+ b.modifyOpInPlace(firstIteration, [&]() {
+ firstIteration.getUpperBoundMutable().assign(splitBound);
+ });
// Update main loop with new lower bound.
b.modifyOpInPlace(forOp, [&]() {
forOp.getInitArgsMutable().assign(firstIteration->getResults());
diff --git a/mlir/test/Dialect/SCF/for-loop-peeling-front.mlir b/mlir/test/Dialect/SCF/for-loop-peeling-front.mlir
index fe3b3e686a3e4..dcf0ecdff6931 100644
--- a/mlir/test/Dialect/SCF/for-loop-peeling-front.mlir
+++ b/mlir/test/Dialect/SCF/for-loop-peeling-front.mlir
@@ -8,7 +8,7 @@
// CHECK-DAG: %[[C17:.*]] = arith.constant 17 : index
// CHECK: %[[FIRST:.*]] = scf.for %[[IV:.*]] = %[[C0]] to %[[C4]]
// CHECK-SAME: step %[[C4]] iter_args(%[[ACC:.*]] = %[[C0_I32]]) -> (i32) {
-// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C4]], %[[IV]])[%[[C4]]]
+// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C17]], %[[IV]])[%[[C4]]]
// CHECK: %[[CAST:.*]] = arith.index_cast %[[MIN]] : index to i32
// CHECK: %[[INIT:.*]] = arith.addi %[[ACC]], %[[CAST]] : i32
// CHECK: scf.yield %[[INIT]]
@@ -35,7 +35,49 @@ func.func @fully_static_bounds() -> i32 {
}
return %r : i32
}
+// -----
+// CHECK-LABEL: func.func @static_two_terations_ub_used_in_loop(
+// CHECK-SAME: %[[IFM1:.*]]: memref<1xi32>) -> i32 {
+// CHECK: %[[C0_I32:.*]] = arith.constant 0 : i32
+// CHECK: %[[C0_IDX:.*]] = arith.constant 0 : index
+// CHECK: %[[C4_IDX:.*]] = arith.constant 4 : index
+// CHECK: %[[C7_IDX:.*]] = arith.constant 7 : index
+// CHECK: %[[FOR1:.*]] = scf.for %[[IV1:.*]] = %[[C0_IDX]] to %[[C4_IDX]] step %[[C4_IDX]] iter_args(%[[ARG1:.*]] = %[[C0_I32]]) -> (i32) {
+// CHECK: %[[AFFINE_MIN1:.*]] = affine.min #map(%[[C7_IDX]], %[[IV1]]){{\[}}%[[C4_IDX]]]
+// CHECK: %[[CAST1:.*]] = arith.index_cast %[[AFFINE_MIN1]] : index to i32
+// CHECK: %[[ADDI1:.*]] = arith.addi %[[ARG1]], %[[CAST1]] : i32
+// CHECK: %[[LOAD1:.*]] = memref.load %[[IFM1]]{{\[}}%[[C7_IDX]]] : memref<1xi32>
+// CHECK: %[[ADDI2:.*]] = arith.addi %[[ADDI1]], %[[LOAD1]] : i32
+// CHECK: scf.yield %[[ADDI2]] : i32
+// CHECK: }
+// CHECK: %[[FOR2:.*]] = scf.for %[[IV2:.*]] = %[[C4_IDX]] to %[[C7_IDX]] step %[[C4_IDX]] iter_args(%[[ARG2:.*]] = %[[RESULT1:.*]]) -> (i32) {
+// CHECK: %[[AFFINE_MIN2:.*]] = affine.min #map(%[[C7_IDX]], %[[IV2]]){{\[}}%[[C4_IDX]]]
+// CHECK: %[[CAST2:.*]] = arith.index_cast %[[AFFINE_MIN2]] : index to i32
+// CHECK: %[[ADDI3:.*]] = arith.addi %[[ARG2]], %[[CAST2]] : i32
+// CHECK: %[[LOAD2:.*]] = memref.load %[[IFM1]]{{\[}}%[[C7_IDX]]] : memref<1xi32>
+// CHECK: %[[ADDI4:.*]] = arith.addi %[[ADDI3]], %[[LOAD2]] : i32
+// CHECK: scf.yield %[[ADDI4]] : i32
+// CHECK: }
+// CHECK: return %[[RESULT2:.*]] : i32
+// CHECK: }
+
+#map = affine_map<(d0, d1)[s0] -> (s0, d0 - d1)>
+func.func @static_two_terations_ub_used_in_loop(%arg0: memref<1xi32>) -> i32 {
+ %c0_i32 = arith.constant 0 : i32
+ %lb = arith.constant 0 : index
+ %step = arith.constant 4 : index
+ %ub = arith.constant 7 : index
+ %r = scf.for %iv = %lb to %ub step %step iter_args(%arg = %c0_i32) -> i32 {
+ %s = affine.min #map(%ub, %iv)[%step]
+ %casted = arith.index_cast %s : index to i32
+ %0 = arith.addi %arg, %casted : i32
+ %1 = memref.load %arg0[%ub] : memref<1xi32>
+ %result = arith.addi %0, %1 : i32
+ scf.yield %result : i32
+ }
+ return %r : i32
+}
// -----
// CHECK-DAG: #[[MAP:.*]] = affine_map<(d0, d1)[s0] -> (4, d0 - d1)>
@@ -44,7 +86,7 @@ func.func @fully_static_bounds() -> i32 {
// CHECK-DAG: %[[C4:.*]] = arith.constant 4 : index
// CHECK-DAG: %[[C0:.*]] = arith.constant 0 : index
// CHECK: scf.for %[[IV:.*]] = %[[C0]] to %[[C4]] step %[[C4]] {
-// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C4]], %[[IV]])[%[[C4]]]
+// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[UB]], %[[IV]])[%[[C4]]]
// CHECK: %[[LOAD:.*]] = memref.load %[[MEMREF]][]
// CHECK: %[[CAST:.*]] = arith.index_cast %[[MIN]]
// CHECK: %[[ADD:.*]] = arith.addi %[[LOAD]], %[[CAST]] : i32
@@ -83,7 +125,7 @@ func.func @no_loop_results(%ub : index, %d : memref<i32>) {
// CHECK: %[[NEW_UB:.*]] = affine.apply #[[MAP0]]()[%[[LB]], %[[STEP]]]
// CHECK: %[[FIRST:.*]] = scf.for %[[IV:.*]] = %[[LB]] to %[[NEW_UB]]
// CHECK-SAME: step %[[STEP]] iter_args(%[[ACC:.*]] = %[[C0_I32]]) -> (i32) {
-// CHECK: %[[MIN:.*]] = affine.min #[[MAP1]](%[[NEW_UB]], %[[IV]])[%[[STEP]]]
+// CHECK: %[[MIN:.*]] = affine.min #[[MAP1]](%[[UB]], %[[IV]])[%[[STEP]]]
// CHECK: %[[CAST:.*]] = arith.index_cast %[[MIN]] : index to i32
// CHECK: %[[ADD:.*]] = arith.addi %[[ACC]], %[[CAST]] : i32
// CHECK: scf.yield %[[ADD]]
@@ -119,7 +161,7 @@ func.func @fully_dynamic_bounds(%lb : index, %ub: index, %step: index) -> i32 {
// CHECK-DAG: %[[C6:.*]] = arith.constant 6 : index
// CHECK: %[[FIRST:.*]] = scf.for %[[IV:.*]] = %[[C2]] to %[[C6]]
// CHECK-SAME: step %[[C4]] iter_args(%[[ACC:.*]] = %[[C0_I32]]) -> (i32) {
-// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C6]], %[[IV]])[%[[C4]]]
+// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C8]], %[[IV]])[%[[C4]]]
// CHECK: %[[CAST:.*]] = arith.index_cast %[[MIN]] : index to i32
// CHECK: %[[INIT:.*]] = arith.addi %[[ACC]], %[[CAST]] : i32
// CHECK: scf.yield %[[INIT]]
diff --git a/mlir/test/Dialect/SCF/for-loop-peeling.mlir b/mlir/test/Dialect/SCF/for-loop-peeling.mlir
index be58548b1fcfe..cfcf19e5c2dee 100644
--- a/mlir/test/Dialect/SCF/for-loop-peeling.mlir
+++ b/mlir/test/Dialect/SCF/for-loop-peeling.mlir
@@ -35,6 +35,35 @@ func.func @fully_dynamic_bounds(%lb : index, %ub: index, %step: index) -> i32 {
// -----
+// CHECK-LABEL: func.func @static_two_terations_ub_used_in_loop(
+// CHECK-SAME: %[[IFM1:.*]]: memref<1xi32>) -> i32 {
+// CHECK: %[[C7_I32:.*]] = arith.constant 7 : i32
+// CHECK: %[[C7_IDX:.*]] = arith.constant 7 : index
+// CHECK: %[[LOAD1:.*]] = memref.load %[[IFM1]]{{\[}}%[[C7_IDX]]] : memref<1xi32>
+// CHECK: %[[ADDI1:.*]] = arith.addi %[[LOAD1]], %[[C7_I32]] : i32
+// CHECK: %[[LOAD2:.*]] = memref.load %[[IFM1]]{{\[}}%[[C7_IDX]]] : memref<1xi32>
+// CHECK: %[[ADDI2:.*]] = arith.addi %[[ADDI1]], %[[LOAD2]] : i32
+// CHECK: return %[[ADDI2]] : i32
+// CHECK: }
+
+#map = affine_map<(d0, d1)[s0] -> (s0, d0 - d1)>
+func.func @static_two_terations_ub_used_in_loop(%arg0: memref<1xi32>) -> i32 {
+ %c0_i32 = arith.constant 0 : i32
+ %lb = arith.constant 0 : index
+ %step = arith.constant 4 : index
+ %ub = arith.constant 7 : index
+ %r = scf.for %iv = %lb to %ub step %step iter_args(%arg = %c0_i32) -> i32 {
+ %s = affine.min #map(%ub, %iv)[%step]
+ %casted = arith.index_cast %s : index to i32
+ %0 = arith.addi %arg, %casted : i32
+ %1 = memref.load %arg0[%ub] : memref<1xi32>
+ %result = arith.addi %0, %1 : i32
+ scf.yield %result : i32
+ }
+ return %r : i32
+}
+// -----
+
// CHECK: func @fully_static_bounds(
// CHECK-DAG: %[[C0_I32:.*]] = arith.constant 0 : i32
// CHECK-DAG: %[[C1_I32:.*]] = arith.constant 1 : i32
|
|
@llvm/pr-subscribers-mlir Author: None (ddubov100) ChangesCurrently when peeling first iteration - any mention of ub within the loop body is replaced with new ub in peeled out first iteration. Another thing is that this implementation is opposite to how peel_last works. I added test which presents this: static_two_terations_ub_used_in_loop, which I added to both front and last lit tests files. I added comments within the lit tests which explain why current implementation is correct and previous cause bugs. Full diff: https://github.com/llvm/llvm-project/pull/163720.diff 3 Files Affected:
diff --git a/mlir/lib/Dialect/SCF/Transforms/LoopSpecialization.cpp b/mlir/lib/Dialect/SCF/Transforms/LoopSpecialization.cpp
index e3717aa9d940e..43fbcbae7791b 100644
--- a/mlir/lib/Dialect/SCF/Transforms/LoopSpecialization.cpp
+++ b/mlir/lib/Dialect/SCF/Transforms/LoopSpecialization.cpp
@@ -241,9 +241,10 @@ LogicalResult mlir::scf::peelForLoopFirstIteration(RewriterBase &b, ForOp forOp,
// Peel the first iteration.
IRMapping map;
- map.map(forOp.getUpperBound(), splitBound);
firstIteration = cast<ForOp>(b.clone(*forOp.getOperation(), map));
-
+ b.modifyOpInPlace(firstIteration, [&]() {
+ firstIteration.getUpperBoundMutable().assign(splitBound);
+ });
// Update main loop with new lower bound.
b.modifyOpInPlace(forOp, [&]() {
forOp.getInitArgsMutable().assign(firstIteration->getResults());
diff --git a/mlir/test/Dialect/SCF/for-loop-peeling-front.mlir b/mlir/test/Dialect/SCF/for-loop-peeling-front.mlir
index fe3b3e686a3e4..dcf0ecdff6931 100644
--- a/mlir/test/Dialect/SCF/for-loop-peeling-front.mlir
+++ b/mlir/test/Dialect/SCF/for-loop-peeling-front.mlir
@@ -8,7 +8,7 @@
// CHECK-DAG: %[[C17:.*]] = arith.constant 17 : index
// CHECK: %[[FIRST:.*]] = scf.for %[[IV:.*]] = %[[C0]] to %[[C4]]
// CHECK-SAME: step %[[C4]] iter_args(%[[ACC:.*]] = %[[C0_I32]]) -> (i32) {
-// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C4]], %[[IV]])[%[[C4]]]
+// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C17]], %[[IV]])[%[[C4]]]
// CHECK: %[[CAST:.*]] = arith.index_cast %[[MIN]] : index to i32
// CHECK: %[[INIT:.*]] = arith.addi %[[ACC]], %[[CAST]] : i32
// CHECK: scf.yield %[[INIT]]
@@ -35,7 +35,49 @@ func.func @fully_static_bounds() -> i32 {
}
return %r : i32
}
+// -----
+// CHECK-LABEL: func.func @static_two_terations_ub_used_in_loop(
+// CHECK-SAME: %[[IFM1:.*]]: memref<1xi32>) -> i32 {
+// CHECK: %[[C0_I32:.*]] = arith.constant 0 : i32
+// CHECK: %[[C0_IDX:.*]] = arith.constant 0 : index
+// CHECK: %[[C4_IDX:.*]] = arith.constant 4 : index
+// CHECK: %[[C7_IDX:.*]] = arith.constant 7 : index
+// CHECK: %[[FOR1:.*]] = scf.for %[[IV1:.*]] = %[[C0_IDX]] to %[[C4_IDX]] step %[[C4_IDX]] iter_args(%[[ARG1:.*]] = %[[C0_I32]]) -> (i32) {
+// CHECK: %[[AFFINE_MIN1:.*]] = affine.min #map(%[[C7_IDX]], %[[IV1]]){{\[}}%[[C4_IDX]]]
+// CHECK: %[[CAST1:.*]] = arith.index_cast %[[AFFINE_MIN1]] : index to i32
+// CHECK: %[[ADDI1:.*]] = arith.addi %[[ARG1]], %[[CAST1]] : i32
+// CHECK: %[[LOAD1:.*]] = memref.load %[[IFM1]]{{\[}}%[[C7_IDX]]] : memref<1xi32>
+// CHECK: %[[ADDI2:.*]] = arith.addi %[[ADDI1]], %[[LOAD1]] : i32
+// CHECK: scf.yield %[[ADDI2]] : i32
+// CHECK: }
+// CHECK: %[[FOR2:.*]] = scf.for %[[IV2:.*]] = %[[C4_IDX]] to %[[C7_IDX]] step %[[C4_IDX]] iter_args(%[[ARG2:.*]] = %[[RESULT1:.*]]) -> (i32) {
+// CHECK: %[[AFFINE_MIN2:.*]] = affine.min #map(%[[C7_IDX]], %[[IV2]]){{\[}}%[[C4_IDX]]]
+// CHECK: %[[CAST2:.*]] = arith.index_cast %[[AFFINE_MIN2]] : index to i32
+// CHECK: %[[ADDI3:.*]] = arith.addi %[[ARG2]], %[[CAST2]] : i32
+// CHECK: %[[LOAD2:.*]] = memref.load %[[IFM1]]{{\[}}%[[C7_IDX]]] : memref<1xi32>
+// CHECK: %[[ADDI4:.*]] = arith.addi %[[ADDI3]], %[[LOAD2]] : i32
+// CHECK: scf.yield %[[ADDI4]] : i32
+// CHECK: }
+// CHECK: return %[[RESULT2:.*]] : i32
+// CHECK: }
+
+#map = affine_map<(d0, d1)[s0] -> (s0, d0 - d1)>
+func.func @static_two_terations_ub_used_in_loop(%arg0: memref<1xi32>) -> i32 {
+ %c0_i32 = arith.constant 0 : i32
+ %lb = arith.constant 0 : index
+ %step = arith.constant 4 : index
+ %ub = arith.constant 7 : index
+ %r = scf.for %iv = %lb to %ub step %step iter_args(%arg = %c0_i32) -> i32 {
+ %s = affine.min #map(%ub, %iv)[%step]
+ %casted = arith.index_cast %s : index to i32
+ %0 = arith.addi %arg, %casted : i32
+ %1 = memref.load %arg0[%ub] : memref<1xi32>
+ %result = arith.addi %0, %1 : i32
+ scf.yield %result : i32
+ }
+ return %r : i32
+}
// -----
// CHECK-DAG: #[[MAP:.*]] = affine_map<(d0, d1)[s0] -> (4, d0 - d1)>
@@ -44,7 +86,7 @@ func.func @fully_static_bounds() -> i32 {
// CHECK-DAG: %[[C4:.*]] = arith.constant 4 : index
// CHECK-DAG: %[[C0:.*]] = arith.constant 0 : index
// CHECK: scf.for %[[IV:.*]] = %[[C0]] to %[[C4]] step %[[C4]] {
-// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C4]], %[[IV]])[%[[C4]]]
+// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[UB]], %[[IV]])[%[[C4]]]
// CHECK: %[[LOAD:.*]] = memref.load %[[MEMREF]][]
// CHECK: %[[CAST:.*]] = arith.index_cast %[[MIN]]
// CHECK: %[[ADD:.*]] = arith.addi %[[LOAD]], %[[CAST]] : i32
@@ -83,7 +125,7 @@ func.func @no_loop_results(%ub : index, %d : memref<i32>) {
// CHECK: %[[NEW_UB:.*]] = affine.apply #[[MAP0]]()[%[[LB]], %[[STEP]]]
// CHECK: %[[FIRST:.*]] = scf.for %[[IV:.*]] = %[[LB]] to %[[NEW_UB]]
// CHECK-SAME: step %[[STEP]] iter_args(%[[ACC:.*]] = %[[C0_I32]]) -> (i32) {
-// CHECK: %[[MIN:.*]] = affine.min #[[MAP1]](%[[NEW_UB]], %[[IV]])[%[[STEP]]]
+// CHECK: %[[MIN:.*]] = affine.min #[[MAP1]](%[[UB]], %[[IV]])[%[[STEP]]]
// CHECK: %[[CAST:.*]] = arith.index_cast %[[MIN]] : index to i32
// CHECK: %[[ADD:.*]] = arith.addi %[[ACC]], %[[CAST]] : i32
// CHECK: scf.yield %[[ADD]]
@@ -119,7 +161,7 @@ func.func @fully_dynamic_bounds(%lb : index, %ub: index, %step: index) -> i32 {
// CHECK-DAG: %[[C6:.*]] = arith.constant 6 : index
// CHECK: %[[FIRST:.*]] = scf.for %[[IV:.*]] = %[[C2]] to %[[C6]]
// CHECK-SAME: step %[[C4]] iter_args(%[[ACC:.*]] = %[[C0_I32]]) -> (i32) {
-// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C6]], %[[IV]])[%[[C4]]]
+// CHECK: %[[MIN:.*]] = affine.min #[[MAP]](%[[C8]], %[[IV]])[%[[C4]]]
// CHECK: %[[CAST:.*]] = arith.index_cast %[[MIN]] : index to i32
// CHECK: %[[INIT:.*]] = arith.addi %[[ACC]], %[[CAST]] : i32
// CHECK: scf.yield %[[INIT]]
diff --git a/mlir/test/Dialect/SCF/for-loop-peeling.mlir b/mlir/test/Dialect/SCF/for-loop-peeling.mlir
index be58548b1fcfe..cfcf19e5c2dee 100644
--- a/mlir/test/Dialect/SCF/for-loop-peeling.mlir
+++ b/mlir/test/Dialect/SCF/for-loop-peeling.mlir
@@ -35,6 +35,35 @@ func.func @fully_dynamic_bounds(%lb : index, %ub: index, %step: index) -> i32 {
// -----
+// CHECK-LABEL: func.func @static_two_terations_ub_used_in_loop(
+// CHECK-SAME: %[[IFM1:.*]]: memref<1xi32>) -> i32 {
+// CHECK: %[[C7_I32:.*]] = arith.constant 7 : i32
+// CHECK: %[[C7_IDX:.*]] = arith.constant 7 : index
+// CHECK: %[[LOAD1:.*]] = memref.load %[[IFM1]]{{\[}}%[[C7_IDX]]] : memref<1xi32>
+// CHECK: %[[ADDI1:.*]] = arith.addi %[[LOAD1]], %[[C7_I32]] : i32
+// CHECK: %[[LOAD2:.*]] = memref.load %[[IFM1]]{{\[}}%[[C7_IDX]]] : memref<1xi32>
+// CHECK: %[[ADDI2:.*]] = arith.addi %[[ADDI1]], %[[LOAD2]] : i32
+// CHECK: return %[[ADDI2]] : i32
+// CHECK: }
+
+#map = affine_map<(d0, d1)[s0] -> (s0, d0 - d1)>
+func.func @static_two_terations_ub_used_in_loop(%arg0: memref<1xi32>) -> i32 {
+ %c0_i32 = arith.constant 0 : i32
+ %lb = arith.constant 0 : index
+ %step = arith.constant 4 : index
+ %ub = arith.constant 7 : index
+ %r = scf.for %iv = %lb to %ub step %step iter_args(%arg = %c0_i32) -> i32 {
+ %s = affine.min #map(%ub, %iv)[%step]
+ %casted = arith.index_cast %s : index to i32
+ %0 = arith.addi %arg, %casted : i32
+ %1 = memref.load %arg0[%ub] : memref<1xi32>
+ %result = arith.addi %0, %1 : i32
+ scf.yield %result : i32
+ }
+ return %r : i32
+}
+// -----
+
// CHECK: func @fully_static_bounds(
// CHECK-DAG: %[[C0_I32:.*]] = arith.constant 0 : i32
// CHECK-DAG: %[[C1_I32:.*]] = arith.constant 1 : i32
|
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
ddubov100
force-pushed
the
users/ddubov100/fixing_peel_first_iteration
branch
from
6037673 to
75308c8
Compare
ddubov100
commented
Oct 16, 2025
|
@matthias-springer @yzhang93 @joker-eph please take a look |
yzhang93
approved these changes
Oct 17, 2025
matthias-springer
approved these changes
Oct 17, 2025
…inside peeled iteration region.
ddubov100
force-pushed
the
users/ddubov100/fixing_peel_first_iteration
branch
from
75308c8 to
28d1f1b
Compare
|
@matthias-springer I addressed your comments, I don't have write permissions, could you please land it for me? |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Currently when peeling first iteration - any mention of ub within the loop body is replaced with new ub in peeled out first iteration.
This introduce bugs in following scenario:
The operations inside the loop intentionally used original ub and need to keep using the original.
Another thing is that this implementation is opposite to how peel_last works. I added test which presents this: static_two_terations_ub_used_in_loop, which I added to both front and last lit tests files.
I added comments within the lit tests which explain why current implementation is correct and previous cause bugs.