[llvm] a34b521 - [Test] Add test showing that Constraint Elimination can deal with case where SCEV fails
Max Kazantsev via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 3 02:41:47 PDT 2022
Author: Max Kazantsev
Date: 2022-10-03T16:41:22+07:00
New Revision: a34b5212ecb94d4f3d49b08e478cb87a30abe308
URL: https://github.com/llvm/llvm-project/commit/a34b5212ecb94d4f3d49b08e478cb87a30abe308
DIFF: https://github.com/llvm/llvm-project/commit/a34b5212ecb94d4f3d49b08e478cb87a30abe308.diff
LOG: [Test] Add test showing that Constraint Elimination can deal with case where SCEV fails
Added:
llvm/test/Transforms/ConstraintElimination/range_checks.ll
Modified:
Removed:
################################################################################
diff --git a/llvm/test/Transforms/ConstraintElimination/range_checks.ll b/llvm/test/Transforms/ConstraintElimination/range_checks.ll
new file mode 100644
index 0000000000000..dcda0e7696ee5
--- /dev/null
+++ b/llvm/test/Transforms/ConstraintElimination/range_checks.ll
@@ -0,0 +1,144 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
+
+; Here we can remove range check because:
+; length >= min_length (from entry)
+; idx < min_length (from in_bounds check)
+; therefore, idx < length is trivially true.
+
+define i32 @test_01(ptr %p, ptr %array, i32 %min_length) {
+; CHECK-LABEL: @test_01(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[LOOP:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ]
+; CHECK-NEXT: [[ELEM_PTR:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[IV]]
+; CHECK-NEXT: [[IDX:%.*]] = load i32, ptr [[ELEM_PTR]], align 4
+; CHECK-NEXT: [[IN_BOUNDS:%.*]] = icmp ult i32 [[IDX]], [[MIN_LENGTH:%.*]]
+; CHECK-NEXT: br i1 [[IN_BOUNDS]], label [[RANGE_CHECK_BLOCK:%.*]], label [[OUT_OF_BOUNDS:%.*]]
+; CHECK: range_check_block:
+; CHECK-NEXT: [[RANGE_CHECK:%.*]] = icmp ult i32 [[IDX]], [[MIN_LENGTH]]
+; CHECK-NEXT: br i1 true, label [[BACKEDGE]], label [[RANGE_CHECK_FAILED:%.*]]
+; CHECK: backedge:
+; CHECK-NEXT: [[ARR_PTR:%.*]] = getelementptr i32, ptr [[ARRAY:%.*]], i32 [[IDX]]
+; CHECK-NEXT: store i32 [[IV]], ptr [[ARR_PTR]], align 4
+; CHECK-NEXT: [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT: [[LOOP_COND:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK: exit:
+; CHECK-NEXT: [[IV_LCSSA:%.*]] = phi i32 [ [[IV]], [[BACKEDGE]] ]
+; CHECK-NEXT: ret i32 [[IV_LCSSA]]
+; CHECK: out_of_bounds:
+; CHECK-NEXT: ret i32 -1
+; CHECK: range_check_failed:
+; CHECK-NEXT: [[IV_LCSSA_RC:%.*]] = phi i32 [ [[IV]], [[RANGE_CHECK_BLOCK]] ]
+; CHECK-NEXT: call void @failed_range_check(i32 [[IV_LCSSA_RC]])
+; CHECK-NEXT: unreachable
+;
+entry:
+ br label %loop
+
+loop: ; preds = %backedge, %entry
+ %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
+ %elem_ptr = getelementptr i32, ptr %p, i32 %iv
+ %idx = load i32, ptr %elem_ptr, align 4
+ %in_bounds = icmp ult i32 %idx, %min_length
+ br i1 %in_bounds, label %range_check_block, label %out_of_bounds
+
+range_check_block: ; preds = %loop
+ %range_check = icmp ult i32 %idx, %min_length
+ br i1 %range_check, label %backedge, label %range_check_failed
+
+backedge: ; preds = %range_check_block
+ %arr_ptr = getelementptr i32, ptr %array, i32 %idx
+ store i32 %iv, ptr %arr_ptr, align 4
+ %iv.next = add i32 %iv, 1
+ %loop_cond = call i1 @cond()
+ br i1 %loop_cond, label %loop, label %exit
+
+exit: ; preds = %backedge
+ %iv.lcssa = phi i32 [ %iv, %backedge ]
+ ret i32 %iv.lcssa
+
+out_of_bounds: ; preds = %loop
+ ret i32 -1
+
+range_check_failed: ; preds = %range_check_block
+ %iv.lcssa.rc = phi i32 [ %iv, %range_check_block ]
+ call void @failed_range_check(i32 %iv.lcssa.rc)
+ unreachable
+}
+
+define i32 @test_02(ptr %p, ptr %array, i32 %length, i32 %min_length) {
+; CHECK-LABEL: @test_02(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[LENGTH_CHECK:%.*]] = icmp uge i32 [[LENGTH:%.*]], [[MIN_LENGTH:%.*]]
+; CHECK-NEXT: br i1 [[LENGTH_CHECK]], label [[LOOP:%.*]], label [[FAILED:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ]
+; CHECK-NEXT: [[ELEM_PTR:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[IV]]
+; CHECK-NEXT: [[IDX:%.*]] = load i32, ptr [[ELEM_PTR]], align 4
+; CHECK-NEXT: [[IN_BOUNDS:%.*]] = icmp ult i32 [[IDX]], [[MIN_LENGTH]]
+; CHECK-NEXT: br i1 [[IN_BOUNDS]], label [[RANGE_CHECK_BLOCK:%.*]], label [[OUT_OF_BOUNDS:%.*]]
+; CHECK: range_check_block:
+; CHECK-NEXT: [[RANGE_CHECK:%.*]] = icmp ult i32 [[IDX]], [[LENGTH]]
+; CHECK-NEXT: br i1 true, label [[BACKEDGE]], label [[RANGE_CHECK_FAILED:%.*]]
+; CHECK: backedge:
+; CHECK-NEXT: [[ARR_PTR:%.*]] = getelementptr i32, ptr [[ARRAY:%.*]], i32 [[IDX]]
+; CHECK-NEXT: store i32 [[IV]], ptr [[ARR_PTR]], align 4
+; CHECK-NEXT: [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT: [[LOOP_COND:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK: exit:
+; CHECK-NEXT: [[IV_LCSSA:%.*]] = phi i32 [ [[IV]], [[BACKEDGE]] ]
+; CHECK-NEXT: ret i32 [[IV_LCSSA]]
+; CHECK: failed:
+; CHECK-NEXT: unreachable
+; CHECK: out_of_bounds:
+; CHECK-NEXT: ret i32 -1
+; CHECK: range_check_failed:
+; CHECK-NEXT: [[IV_LCSSA_RC:%.*]] = phi i32 [ [[IV]], [[RANGE_CHECK_BLOCK]] ]
+; CHECK-NEXT: call void @failed_range_check(i32 [[IV_LCSSA_RC]])
+; CHECK-NEXT: unreachable
+;
+entry:
+ %length_check = icmp uge i32 %length, %min_length
+ br i1 %length_check, label %loop, label %failed
+
+loop: ; preds = %backedge, %entry
+ %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
+ %elem_ptr = getelementptr i32, ptr %p, i32 %iv
+ %idx = load i32, ptr %elem_ptr, align 4
+ %in_bounds = icmp ult i32 %idx, %min_length
+ br i1 %in_bounds, label %range_check_block, label %out_of_bounds
+
+range_check_block: ; preds = %loop
+ %range_check = icmp ult i32 %idx, %length
+ br i1 %range_check, label %backedge, label %range_check_failed
+
+backedge: ; preds = %range_check_block
+ %arr_ptr = getelementptr i32, ptr %array, i32 %idx
+ store i32 %iv, ptr %arr_ptr, align 4
+ %iv.next = add i32 %iv, 1
+ %loop_cond = call i1 @cond()
+ br i1 %loop_cond, label %loop, label %exit
+
+exit: ; preds = %backedge
+ %iv.lcssa = phi i32 [ %iv, %backedge ]
+ ret i32 %iv.lcssa
+
+failed: ; preds = %entry
+ unreachable
+
+out_of_bounds: ; preds = %loop
+ ret i32 -1
+
+range_check_failed: ; preds = %range_check_block
+ %iv.lcssa.rc = phi i32 [ %iv, %range_check_block ]
+ call void @failed_range_check(i32 %iv.lcssa.rc)
+ unreachable
+}
+
+declare i1 @cond()
+
+declare void @failed_range_check(i32)
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