[SimplifyCFG] Make the no-jump-tables attribute also disable switch lookup tables

Differential Revision: https://reviews.llvm.org/D35579

llvm-svn: 309444

2 files changed, 80 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SimplifyCFG/Hexagon/disable-lookup-table.ll b/llvm/test/Transforms/SimplifyCFG/Hexagon/disable-lookup-table.ll
new file mode 100644
index 00000000000..a10c67019f0
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/Hexagon/disable-lookup-table.ll
@@ -0,0 +1,36 @@
+; RUN: opt -S -O2 < %s | FileCheck %s -check-prefix=DISABLE
+; RUN: opt -S -hexagon-emit-lookup-tables=true -O2 < %s | FileCheck %s -check-prefix=DISABLE
+; RUN: opt -S -hexagon-emit-lookup-tables=false -O2 < %s | FileCheck %s -check-prefix=DISABLE
+; The attribute "no-jump-tables"="true" disables the generation of switch generated lookup tables
+
+; DISABLE-NOT: @{{.*}} = private unnamed_addr constant [6 x i32] [i32 9, i32 20, i32 14, i32 22, i32 12, i32 5]
+
+target datalayout = "e-m:e-p:32:32:32-a:0-n16:32-i64:64:64-i32:32:32-i16:16:16-i1:8:8-f32:32:32-f64:64:64-v32:32:32-v64:64:64-v512:512:512-v1024:1024:1024-v2048:2048:2048"
+target triple = "hexagon-unknown--elf"
+
+; Function Attrs: noinline nounwind
+define i32 @foo(i32 %c) #0 {
+entry:
+  switch i32 %c, label %sw.default [
+    i32 42, label %return
+    i32 43, label %sw.bb1
+    i32 44, label %sw.bb2
+    i32 45, label %sw.bb3
+    i32 46, label %sw.bb4
+    i32 47, label %sw.bb5
+    i32 48, label %sw.bb6
+  ]
+
+sw.bb1: br label %return
+sw.bb2: br label %return
+sw.bb3: br label %return
+sw.bb4: br label %return
+sw.bb5: br label %return
+sw.bb6: br label %return
+sw.default: br label %return
+return:
+  %retval.0 = phi i32 [ 15, %sw.default ], [ 1, %sw.bb6 ], [ 62, %sw.bb5 ], [ 27, %sw.bb4 ], [ -1, %sw.bb3 ], [ 0, %sw.bb2 ], [ 123, %sw.bb1 ], [ 55, %entry ]
+  ret i32 %retval.0
+}
+
+attributes #0 = { noinline nounwind "no-jump-tables"="true"}
diff --git a/llvm/test/Transforms/SimplifyCFG/disable-lookup-table.ll b/llvm/test/Transforms/SimplifyCFG/disable-lookup-table.ll
new file mode 100644
index 00000000000..c775389d690
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/disable-lookup-table.ll
@@ -0,0 +1,44 @@
+; RUN: opt < %s -latesimplifycfg -S -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+; In the presence of "-no-jump-tables"="true", late simplifycfg should not
+; convert any switch cases to lookup tables.
+; CHECK: @switch.table.bar = private unnamed_addr constant [4 x i32] [i32 55, i32 123, i32 0, i32 -1]
+; CHECK-LABEL: foo
+; CHECK-NOT: @switch.table.foo = private unnamed_addr constant [4 x i32] [i32 55, i32 123, i32 0, i32 -1]
+
+define i32 @foo(i32 %c) "no-jump-tables"="true" {
+entry:
+  switch i32 %c, label %sw.default [
+    i32 42, label %return
+    i32 43, label %sw.bb1
+    i32 44, label %sw.bb2
+    i32 45, label %sw.bb3
+  ]
+
+sw.bb1: br label %return
+sw.bb2: br label %return
+sw.bb3: br label %return
+sw.default: br label %return
+return:
+  %retval.0 = phi i32 [ 15, %sw.default ],  [ -1, %sw.bb3 ], [ 0, %sw.bb2 ], [ 123, %sw.bb1 ], [ 55, %entry ]
+  ret i32 %retval.0
+}
+
+
+define i32 @bar(i32 %c) {
+entry:
+  switch i32 %c, label %sw.default [
+    i32 42, label %return
+    i32 43, label %sw.bb1
+    i32 44, label %sw.bb2
+    i32 45, label %sw.bb3
+  ]
+
+sw.bb1: br label %return
+sw.bb2: br label %return
+sw.bb3: br label %return
+sw.default: br label %return
+return:
+  %retval.0 = phi i32 [ 15, %sw.default ],  [ -1, %sw.bb3 ], [ 0, %sw.bb2 ], [ 123, %sw.bb1 ], [ 55, %entry ]
+  ret i32 %retval.0
+}
+