From f3254838e47aa0afc36c8ba5af3207c5912972be Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Tue, 30 Oct 2012 11:23:25 +0000 Subject: Use TargetTransformInfo to control switch-to-lookup table transformation When the switch-to-lookup tables transform landed in SimplifyCFG, it was pointed out that this could be inappropriate for some targets. Since there was no way at the time for the pass to know anything about the target, an awkward reverse-transform was added in CodeGenPrepare that turned lookup tables back into switches for some targets. This patch uses the new TargetTransformInfo to determine if a switch should be transformed, and removes CodeGenPrepare::ConvertLoadToSwitch. llvm-svn: 167011 --- .../Transforms/SimplifyCFG/SPARC/lit.local.cfg | 6 ++++ .../SimplifyCFG/SPARC/switch_to_lookup_table.ll | 32 ++++++++++++++++++++++ 2 files changed, 38 insertions(+) create mode 100644 llvm/test/Transforms/SimplifyCFG/SPARC/lit.local.cfg create mode 100644 llvm/test/Transforms/SimplifyCFG/SPARC/switch_to_lookup_table.ll (limited to 'llvm/test/Transforms/SimplifyCFG') diff --git a/llvm/test/Transforms/SimplifyCFG/SPARC/lit.local.cfg b/llvm/test/Transforms/SimplifyCFG/SPARC/lit.local.cfg new file mode 100644 index 00000000000..786fee9e661 --- /dev/null +++ b/llvm/test/Transforms/SimplifyCFG/SPARC/lit.local.cfg @@ -0,0 +1,6 @@ +config.suffixes = ['.ll', '.c', '.cpp'] + +targets = set(config.root.targets_to_build.split()) +if not 'Sparc' in targets: + config.unsupported = True + diff --git a/llvm/test/Transforms/SimplifyCFG/SPARC/switch_to_lookup_table.ll b/llvm/test/Transforms/SimplifyCFG/SPARC/switch_to_lookup_table.ll new file mode 100644 index 00000000000..9d1568557f3 --- /dev/null +++ b/llvm/test/Transforms/SimplifyCFG/SPARC/switch_to_lookup_table.ll @@ -0,0 +1,32 @@ +; RUN: opt < %s -simplifycfg -S -mtriple=sparc-unknown-unknown | FileCheck %s + +; Check that switches are not turned into lookup tables, as this is not +; considered profitable on the target. + +define i32 @f(i32 %c) nounwind uwtable readnone { +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 + +; CHECK: @f +; CHECK-NOT: getelementptr +; CHECK: switch i32 %c +} -- cgit v1.2.3