[llvm] d0920b2 - [Test] Account for possibility to free memory in loop load PRE test

[Max Kazantsev via llvm-commits]

Author: Max Kazantsev
Date: 2021-04-14T19:28:42+07:00
New Revision: d0920b201f7cb7494dff9334725e123283128c95

URL: https://github.com/llvm/llvm-project/commit/d0920b201f7cb7494dff9334725e123283128c95
DIFF: https://github.com/llvm/llvm-project/commit/d0920b201f7cb7494dff9334725e123283128c95.diff

LOG: [Test] Account for possibility to free memory in loop load PRE test

Added: 
    

Modified: 
    llvm/test/Transforms/GVN/PRE/pre-loop-load.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/GVN/PRE/pre-loop-load.ll b/llvm/test/Transforms/GVN/PRE/pre-loop-load.ll
index f1433cfc2263..e268a08d2270 100644
--- a/llvm/test/Transforms/GVN/PRE/pre-loop-load.ll
+++ b/llvm/test/Transforms/GVN/PRE/pre-loop-load.ll
@@ -1,8 +1,9 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -basic-aa -enable-load-pre -enable-pre -gvn -S < %s | FileCheck %s
 
-declare void @side_effect()
-declare i1 @side_effect_cond()
+declare void @side_effect() nofree
+declare i1 @side_effect_cond() nofree
+declare void @may_free_memory()
 
 declare i32 @personality_function()
 
@@ -53,6 +54,104 @@ exit:
   ret i32 %x
 }
 
+; We should NOT PRE here because the function on the cold path may possibly
+; free the memory under the pointer.
+define i32 @test_load_on_cold_path_may_free_memory_neg(i32* %p) {
+; CHECK-LABEL: @test_load_on_cold_path_may_free_memory_neg(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ]
+; CHECK-NEXT:    [[X:%.*]] = load i32, i32* [[P:%.*]], align 4
+; CHECK-NEXT:    [[COND:%.*]] = icmp ne i32 [[X]], 0
+; CHECK-NEXT:    br i1 [[COND]], label [[HOT_PATH:%.*]], label [[COLD_PATH:%.*]]
+; CHECK:       hot_path:
+; CHECK-NEXT:    br label [[BACKEDGE]]
+; CHECK:       cold_path:
+; CHECK-NEXT:    call void @may_free_memory()
+; CHECK-NEXT:    br label [[BACKEDGE]]
+; CHECK:       backedge:
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], [[X]]
+; CHECK-NEXT:    [[LOOP_COND:%.*]] = icmp ult i32 [[IV_NEXT]], 1000
+; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i32 [[X]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry], [%iv.next, %backedge]
+  %x = load i32, i32* %p
+  %cond = icmp ne i32 %x, 0
+  br i1 %cond, label %hot_path, label %cold_path
+
+hot_path:
+  br label %backedge
+
+cold_path:
+  call void @may_free_memory()
+  br label %backedge
+
+backedge:
+  %iv.next = add i32 %iv, %x
+  %loop.cond = icmp ult i32 %iv.next, 1000
+  br i1 %loop.cond, label %loop, label %exit
+
+exit:
+  ret i32 %x
+}
+
+; TODO: Despite the fact that the function may free memory in general, it
+; cannot free memory allocated by alloca.
+define i32 @test_load_on_cold_path_may_free_memory_alloca() {
+; CHECK-LABEL: @test_load_on_cold_path_may_free_memory_alloca(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[P:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @may_free_memory()
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    br i1 undef, label [[HOT_PATH:%.*]], label [[COLD_PATH:%.*]]
+; CHECK:       hot_path:
+; CHECK-NEXT:    br label [[BACKEDGE:%.*]]
+; CHECK:       cold_path:
+; CHECK-NEXT:    call void @may_free_memory()
+; CHECK-NEXT:    br label [[BACKEDGE]]
+; CHECK:       backedge:
+; CHECK-NEXT:    br i1 false, label [[BACKEDGE_LOOP_CRIT_EDGE:%.*]], label [[EXIT:%.*]]
+; CHECK:       backedge.loop_crit_edge:
+; CHECK-NEXT:    br label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i32 undef
+;
+entry:
+  %p = alloca i32
+  call void @may_free_memory()
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry], [%iv.next, %backedge]
+  %x = load i32, i32* %p
+  %cond = icmp ne i32 %x, 0
+  br i1 %cond, label %hot_path, label %cold_path
+
+hot_path:
+  br label %backedge
+
+cold_path:
+  call void @may_free_memory()
+  br label %backedge
+
+backedge:
+  %iv.next = add i32 %iv, %x
+  %loop.cond = icmp ult i32 %iv.next, 1000
+  br i1 %loop.cond, label %loop, label %exit
+
+exit:
+  ret i32 %x
+}
+
+
 ; PRE here is meaningless, so we should not do it.
 define i32 @test_load_on_both_paths(i32* %p) {
 ; CHECK-LABEL: @test_load_on_both_paths(