From b0319962cfdb18da38ef47da621f148fe144b092 Mon Sep 17 00:00:00 2001
From: Hans Wennborg <hans@hanshq.net>
Date: Wed, 7 Nov 2012 21:35:12 +0000
Subject: [PATCH] Only do switch-to-lookup table transformation when
 TargetTransformInfo is available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167552 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Utils/SimplifyCFG.cpp                        | 3 ++-
 test/Transforms/SimplifyCFG/X86/lit.local.cfg               | 6 ++++++
 .../SimplifyCFG/{ => X86}/switch_to_lookup_table.ll         | 2 +-
 test/Transforms/SimplifyCFG/switch_create.ll                | 5 ++---
 4 files changed, 11 insertions(+), 5 deletions(-)
 create mode 100644 test/Transforms/SimplifyCFG/X86/lit.local.cfg
 rename test/Transforms/SimplifyCFG/{ => X86}/switch_to_lookup_table.ll (99%)

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 9823433e861..b33d0d473b1 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -3538,7 +3538,8 @@ static bool SwitchToLookupTable(SwitchInst *SI,
                                 const TargetTransformInfo *TTI) {
   assert(SI->getNumCases() > 1 && "Degenerate switch?");
 
-  if (TTI && !TTI->getScalarTargetTransformInfo()->shouldBuildLookupTables())
+  // Only build lookup table when we have a target that supports it.
+  if (!TTI || !TTI->getScalarTargetTransformInfo()->shouldBuildLookupTables())
     return false;
 
   // FIXME: If the switch is too sparse for a lookup table, perhaps we could
diff --git a/test/Transforms/SimplifyCFG/X86/lit.local.cfg b/test/Transforms/SimplifyCFG/X86/lit.local.cfg
new file mode 100644
index 00000000000..a8ad0f1a28b
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/X86/lit.local.cfg
@@ -0,0 +1,6 @@
+config.suffixes = ['.ll', '.c', '.cpp']
+
+targets = set(config.root.targets_to_build.split())
+if not 'X86' in targets:
+    config.unsupported = True
+
diff --git a/test/Transforms/SimplifyCFG/switch_to_lookup_table.ll b/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll
similarity index 99%
rename from test/Transforms/SimplifyCFG/switch_to_lookup_table.ll
rename to test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll
index 0f5eb6a135d..8a59992f5e6 100644
--- a/test/Transforms/SimplifyCFG/switch_to_lookup_table.ll
+++ b/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -S -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
diff --git a/test/Transforms/SimplifyCFG/switch_create.ll b/test/Transforms/SimplifyCFG/switch_create.ll
index b28e4a45509..546cc75f297 100644
--- a/test/Transforms/SimplifyCFG/switch_create.ll
+++ b/test/Transforms/SimplifyCFG/switch_create.ll
@@ -141,9 +141,8 @@ UnifiedReturnBlock:             ; preds = %shortcirc_done.4, %shortcirc_next.4
         ret i1 %UnifiedRetVal
         
 ; CHECK: @test6
-; CHECK: %switch.tableidx = sub i32 %tmp.2.i, 14
-; CHECK: %0 = icmp ult i32 %switch.tableidx, 6
-; CHECK: select i1 %0, i1 true, i1 false
+; CHECK: %tmp.2.i.off = add i32 %tmp.2.i, -14
+; CHECK: %switch = icmp ult i32 %tmp.2.i.off, 6
 }
 
 define void @test7(i8 zeroext %c, i32 %x) nounwind ssp noredzone {
-- 
2.34.1