[llvm] b9c1d73 - [Test] Add test showing that SCEV fails to evaluate symbolic max for 'and' conditions
Max Kazantsev via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 24 20:52:54 PST 2022
Author: Max Kazantsev
Date: 2022-11-25T11:45:10+07:00
New Revision: b9c1d7372526228b027374bbd369b9d8c2fa9338
URL: https://github.com/llvm/llvm-project/commit/b9c1d7372526228b027374bbd369b9d8c2fa9338
DIFF: https://github.com/llvm/llvm-project/commit/b9c1d7372526228b027374bbd369b9d8c2fa9338.diff
LOG: [Test] Add test showing that SCEV fails to evaluate symbolic max for 'and' conditions
Added:
llvm/test/Analysis/ScalarEvolution/symbolic_max_exit_count.ll
Modified:
Removed:
################################################################################
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 000000000000..8b0ab04e7859
--- /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<scalar-evolution>" < %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: <<Unknown>> 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: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %iv.next = add i32 %iv, -1
+; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %loop_cond = call i1 @cond()
+; CHECK-NEXT: --> %loop_cond U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT: Determining loop execution counts for: @test_simple_case
+; CHECK-NEXT: Loop %loop: <multiple exits> 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: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %fake_1 = call i1 @cond()
+; CHECK-NEXT: --> %fake_1 U: full-set S: full-set Exits: <<Unknown>> 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: <<Unknown>> 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: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %fake_2 = call i1 @cond()
+; CHECK-NEXT: --> %fake_2 U: full-set S: full-set Exits: <<Unknown>> 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: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT: %iv.next = add i32 %iv, -1
+; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %loop_cond = call i1 @cond()
+; CHECK-NEXT: --> %loop_cond U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT: Determining loop execution counts for: @test_litter_conditions
+; CHECK-NEXT: Loop %loop: <multiple exits> 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: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %fake_1 = call i1 @cond()
+; CHECK-NEXT: --> %fake_1 U: full-set S: full-set Exits: <<Unknown>> 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: <<Unknown>> 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: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %fake_2 = call i1 @cond()
+; CHECK-NEXT: --> %fake_2 U: full-set S: full-set Exits: <<Unknown>> 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: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT: %iv.next = add i32 %iv, -1
+; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %loop_cond = call i1 @cond()
+; CHECK-NEXT: --> %loop_cond U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT: Determining loop execution counts for: @test_litter_conditions_bad_context
+; CHECK-NEXT: Loop %loop: <multiple exits> 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: <<Unknown>> 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: <<Unknown>> 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: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT: %iv.next = add i32 %iv, -1
+; CHECK-NEXT: --> {(-1 + %start),+,-1}<%loop> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
+; CHECK-NEXT: %loop_cond = call i1 @cond()
+; CHECK-NEXT: --> %loop_cond U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT: Determining loop execution counts for: @test_and_conditions
+; CHECK-NEXT: Loop %loop: <multiple exits> 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
+}
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