From b9c1d7372526228b027374bbd369b9d8c2fa9338 Mon Sep 17 00:00:00 2001 From: Max Kazantsev Date: Fri, 25 Nov 2022 11:45:10 +0700 Subject: [PATCH] [Test] Add test showing that SCEV fails to evaluate symbolic max for 'and' conditions --- .../ScalarEvolution/symbolic_max_exit_count.ll | 230 +++++++++++++++++++++ 1 file changed, 230 insertions(+) create mode 100644 llvm/test/Analysis/ScalarEvolution/symbolic_max_exit_count.ll diff --git a/llvm/test/Analysis/ScalarEvolution/symbolic_max_exit_count.ll b/llvm/test/Analysis/ScalarEvolution/symbolic_max_exit_count.ll new file mode 100644 index 0000000..8b0ab04 --- /dev/null +++ b/llvm/test/Analysis/ScalarEvolution/symbolic_max_exit_count.ll @@ -0,0 +1,230 @@ +; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py +; RUN: opt -disable-output "-passes=print" < %s 2>&1 | FileCheck %s + +declare i1 @cond() + +define i32 @test_simple_case(i32 %start, i32 %len) { +; CHECK-LABEL: 'test_simple_case' +; CHECK-NEXT: Classifying expressions for: @test_simple_case +; CHECK-NEXT: %iv = phi i32 [ %start, %entry ], [ %iv.next, %backedge ] +; CHECK-NEXT: --> {%start,+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %iv.minus.1 = add i32 %iv, -1 +; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %iv.next = add i32 %iv, -1 +; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %loop_cond = call i1 @cond() +; CHECK-NEXT: --> %loop_cond U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: Determining loop execution counts for: @test_simple_case +; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count. +; CHECK-NEXT: exit count for loop: %start +; CHECK-NEXT: exit count for range_check_block: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: exit count for backedge: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: Loop %loop: constant max backedge-taken count is -1 +; CHECK-NEXT: Loop %loop: symbolic max backedge-taken count is %start +; CHECK-NEXT: symbolic max exit count for loop: %start +; CHECK-NEXT: symbolic max exit count for range_check_block: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: symbolic max exit count for backedge: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count. +; +entry: + br label %loop + +loop: + %iv = phi i32 [%start, %entry], [%iv.next, %backedge] + %zero_check = icmp ne i32 %iv, 0 + br i1 %zero_check, label %range_check_block, label %failed_1 + +range_check_block: + %iv.minus.1 = add i32 %iv, -1 + %range_check = icmp ult i32 %iv.minus.1, %len + br i1 %range_check, label %backedge, label %failed_2 + +backedge: + %iv.next = add i32 %iv, -1 + %loop_cond = call i1 @cond() + br i1 %loop_cond, label %done, label %loop + +done: + ret i32 %iv + +failed_1: + ret i32 -1 + +failed_2: + ret i32 -2 +} + +; TODO: Symbolic max can be %start +define i32 @test_litter_conditions(i32 %start, i32 %len) { +; CHECK-LABEL: 'test_litter_conditions' +; CHECK-NEXT: Classifying expressions for: @test_litter_conditions +; CHECK-NEXT: %iv = phi i32 [ %start, %entry ], [ %iv.next, %backedge ] +; CHECK-NEXT: --> {%start,+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %fake_1 = call i1 @cond() +; CHECK-NEXT: --> %fake_1 U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %and_1 = and i1 %zero_check, %fake_1 +; CHECK-NEXT: --> (%zero_check umin %fake_1) U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %iv.minus.1 = add i32 %iv, -1 +; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %fake_2 = call i1 @cond() +; CHECK-NEXT: --> %fake_2 U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %and_2 = and i1 %range_check, %fake_2 +; CHECK-NEXT: --> (%range_check umin %fake_2) U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %iv.next = add i32 %iv, -1 +; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %loop_cond = call i1 @cond() +; CHECK-NEXT: --> %loop_cond U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: Determining loop execution counts for: @test_litter_conditions +; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count. +; CHECK-NEXT: exit count for loop: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: exit count for range_check_block: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: exit count for backedge: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: Loop %loop: constant max backedge-taken count is -1 +; CHECK-NEXT: Loop %loop: Unpredictable symbolic max backedge-taken count. +; CHECK-NEXT: symbolic max exit count for loop: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: symbolic max exit count for range_check_block: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: symbolic max exit count for backedge: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count. +; +entry: + br label %loop + +loop: + %iv = phi i32 [%start, %entry], [%iv.next, %backedge] + %zero_check = icmp ne i32 %iv, 0 + %fake_1 = call i1 @cond() + %and_1 = and i1 %zero_check, %fake_1 + br i1 %and_1, label %range_check_block, label %failed_1 + +range_check_block: + %iv.minus.1 = add i32 %iv, -1 + %range_check = icmp ult i32 %iv.minus.1, %len + %fake_2 = call i1 @cond() + %and_2 = and i1 %range_check, %fake_2 + br i1 %and_2, label %backedge, label %failed_2 + +backedge: + %iv.next = add i32 %iv, -1 + %loop_cond = call i1 @cond() + br i1 %loop_cond, label %done, label %loop + +done: + ret i32 %iv + +failed_1: + ret i32 -1 + +failed_2: + ret i32 -2 +} + +; TODO: Symbolic max can be %start +define i32 @test_litter_conditions_bad_context(i32 %start, i32 %len) { +; CHECK-LABEL: 'test_litter_conditions_bad_context' +; CHECK-NEXT: Classifying expressions for: @test_litter_conditions_bad_context +; CHECK-NEXT: %iv = phi i32 [ %start, %entry ], [ %iv.next, %backedge ] +; CHECK-NEXT: --> {%start,+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %fake_1 = call i1 @cond() +; CHECK-NEXT: --> %fake_1 U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %and_1 = and i1 %zero_check, %fake_1 +; CHECK-NEXT: --> (%zero_check umin %fake_1) U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %iv.minus.1 = add i32 %iv, -1 +; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %fake_2 = call i1 @cond() +; CHECK-NEXT: --> %fake_2 U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %and_2 = and i1 %range_check, %fake_2 +; CHECK-NEXT: --> (%range_check umin %fake_2) U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %iv.next = add i32 %iv, -1 +; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %loop_cond = call i1 @cond() +; CHECK-NEXT: --> %loop_cond U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: Determining loop execution counts for: @test_litter_conditions_bad_context +; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count. +; CHECK-NEXT: exit count for loop: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: exit count for range_check_block: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: exit count for backedge: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: Loop %loop: constant max backedge-taken count is -1 +; CHECK-NEXT: Loop %loop: Unpredictable symbolic max backedge-taken count. +; CHECK-NEXT: symbolic max exit count for loop: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: symbolic max exit count for range_check_block: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: symbolic max exit count for backedge: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count. +; +entry: + br label %loop + +loop: + %iv = phi i32 [%start, %entry], [%iv.next, %backedge] + %zero_check = icmp ne i32 %iv, 0 + %fake_1 = call i1 @cond() + %and_1 = and i1 %zero_check, %fake_1 + %iv.minus.1 = add i32 %iv, -1 + %range_check = icmp ult i32 %iv.minus.1, %len + %fake_2 = call i1 @cond() + %and_2 = and i1 %range_check, %fake_2 + br i1 %and_1, label %range_check_block, label %failed_1 + +range_check_block: + br i1 %and_2, label %backedge, label %failed_2 + +backedge: + %iv.next = add i32 %iv, -1 + %loop_cond = call i1 @cond() + br i1 %loop_cond, label %done, label %loop + +done: + ret i32 %iv + +failed_1: + ret i32 -1 + +failed_2: + ret i32 -2 +} + +; TODO: Symbolic max can be %start +define i32 @test_and_conditions(i32 %start, i32 %len) { +; CHECK-LABEL: 'test_and_conditions' +; CHECK-NEXT: Classifying expressions for: @test_and_conditions +; CHECK-NEXT: %iv = phi i32 [ %start, %entry ], [ %iv.next, %backedge ] +; CHECK-NEXT: --> {%start,+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %iv.minus.1 = add i32 %iv, -1 +; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %both_checks = and i1 %zero_check, %range_check +; CHECK-NEXT: --> (%range_check umin %zero_check) U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: %iv.next = add i32 %iv, -1 +; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Computable } +; CHECK-NEXT: %loop_cond = call i1 @cond() +; CHECK-NEXT: --> %loop_cond U: full-set S: full-set Exits: <> LoopDispositions: { %loop: Variant } +; CHECK-NEXT: Determining loop execution counts for: @test_and_conditions +; CHECK-NEXT: Loop %loop: Unpredictable backedge-taken count. +; CHECK-NEXT: exit count for loop: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: exit count for backedge: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: Loop %loop: constant max backedge-taken count is -1 +; CHECK-NEXT: Loop %loop: Unpredictable symbolic max backedge-taken count. +; CHECK-NEXT: symbolic max exit count for loop: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: symbolic max exit count for backedge: ***COULDNOTCOMPUTE*** +; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count. +; +entry: + br label %loop + +loop: + %iv = phi i32 [%start, %entry], [%iv.next, %backedge] + %zero_check = icmp ne i32 %iv, 0 + %iv.minus.1 = add i32 %iv, -1 + %range_check = icmp ult i32 %iv.minus.1, %len + %both_checks = and i1 %zero_check, %range_check + br i1 %both_checks, label %backedge, label %failed + +backedge: + %iv.next = add i32 %iv, -1 + %loop_cond = call i1 @cond() + br i1 %loop_cond, label %done, label %loop + +done: + ret i32 %iv + +failed: + ret i32 -3 +} -- 2.7.4