1 files changed, 118 insertions, 0 deletions
diff --git a/llvm/test/Transforms/GVN/PRE/pre-load-implicit-cf-updates.ll b/llvm/test/Transforms/GVN/PRE/pre-load-implicit-cf-updates.ll
new file mode 100644
index 00000000000..c131e923997
--- /dev/null
+++ b/llvm/test/Transforms/GVN/PRE/pre-load-implicit-cf-updates.ll
@@ -0,0 +1,118 @@
+; RUN: opt -S -gvn -enable-load-pre < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; These tests exercise situations when instructions that were first instructions
+; with implicit control flow get removed. We make sure that after that we don't
+; face crashes and are still able to perform PRE correctly.
+
+declare i32 @foo(i32 %arg) #0
+
+define hidden void @test_01(i32 %x, i32 %y) {
+
+; c2 only throws if c1 throws, so it can be safely removed and then PRE can
+; hoist the load out of loop.
+
+; CHECK-LABEL: @test_01
+; CHECK:       entry:
+; CHECK-NEXT:    %c1 = call i32 @foo(i32 %x)
+; CHECK-NEXT:    %val.pre = load i32, i32* null, align 8
+; CHECK-NEXT:    br label %loop
+; CHECK:       loop:
+; CHECK-NEXT:    %c3 = call i32 @foo(i32 %val.pre)
+; CHECK-NEXT:    br label %loop
+
+entry:
+  %c1 = call i32 @foo(i32 %x)
+  br label %loop
+
+loop:
+  %c2 = call i32 @foo(i32 %x)
+  %val = load i32, i32* null, align 8
+  %c3 = call i32 @foo(i32 %val)
+  br label %loop
+}
+
+define hidden void @test_02(i32 %x, i32 %y) {
+
+; PRE is not allowed because c2 may throw.
+
+; CHECK-LABEL: @test_02
+; CHECK:       entry:
+; CHECK-NEXT:    %c1 = call i32 @foo(i32 %x)
+; CHECK-NEXT:    br label %loop
+; CHECK:       loop:
+; CHECK-NEXT:    %c2 = call i32 @foo(i32 %y)
+; CHECK-NEXT:    %val = load i32, i32* null, align 8
+; CHECK-NEXT:    %c3 = call i32 @foo(i32 %val)
+; CHECK-NEXT:    br label %loop
+
+entry:
+  %c1 = call i32 @foo(i32 %x)
+  br label %loop
+
+loop:
+  %c2 = call i32 @foo(i32 %y)
+  %val = load i32, i32* null, align 8
+  %c3 = call i32 @foo(i32 %val)
+  br label %loop
+}
+
+define hidden void @test_03(i32 %x, i32 %y) {
+
+; PRE of load is allowed because c2 only throws if c1 throws. c3 should
+; not be eliminated. c4 is eliminated because it only throws if c3 throws.
+
+; CHECK-LABEL: @test_03
+; CHECK:       entry:
+; CHECK-NEXT:    %c1 = call i32 @foo(i32 %x)
+; CHECK-NEXT:    %val.pre = load i32, i32* null, align 8
+; CHECK-NEXT:    br label %loop
+; CHECK:       loop:
+; CHECK-NEXT:    %c3 = call i32 @foo(i32 %y)
+; CHECK-NEXT:    %c5 = call i32 @foo(i32 %val.pre)
+; CHECK-NEXT:    br label %loop
+
+entry:
+  %c1 = call i32 @foo(i32 %x)
+  br label %loop
+
+loop:
+  %c2 = call i32 @foo(i32 %x)
+  %val = load i32, i32* null, align 8
+  %c3 = call i32 @foo(i32 %y)
+  %val2 = load i32, i32* null, align 8
+  %c4 = call i32 @foo(i32 %y)
+  %c5 = call i32 @foo(i32 %val)
+  br label %loop
+}
+
+define hidden void @test_04(i32 %x, i32 %y) {
+
+; PRE is not allowed even after we remove c2 because now c3 prevents us from it.
+
+; CHECK-LABEL: @test_04
+; CHECK:       entry:
+; CHECK-NEXT:    %c1 = call i32 @foo(i32 %x)
+; CHECK-NEXT:    br label %loop
+; CHECK:       loop:
+; CHECK-NEXT:    %c3 = call i32 @foo(i32 %y)
+; CHECK-NEXT:    %val = load i32, i32* null, align 8
+; CHECK-NEXT:    %c5 = call i32 @foo(i32 %val)
+; CHECK-NEXT:    br label %loop
+
+entry:
+  %c1 = call i32 @foo(i32 %x)
+  br label %loop
+
+loop:
+  %c2 = call i32 @foo(i32 %x)
+  %c3 = call i32 @foo(i32 %y)
+  %val = load i32, i32* null, align 8
+  %c4 = call i32 @foo(i32 %y)
+  %c5 = call i32 @foo(i32 %val)
+  br label %loop
+}
+
+attributes #0 = { readnone }