llvm-6502/test/Transforms/SimplifyCFG/switch_formation.dbg.ll
Benjamin Kramer 56442dfdcf SimplifyCFG: Turn switches into sub+icmp+branch if possible.
This makes the job of the later optzn passes easier, allowing the vast amount of
icmp transforms to chew on it.

We transform 840 switches in gcc.c, leading to a 16k byte shrink of the resulting
binary on i386-linux.

The testcase from README.txt now compiles into
  decl  %edi
  cmpl  $3, %edi
  sbbl  %eax, %eax
  andl  $1, %eax
  ret

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124724 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-02 15:56:22 +00:00

51 lines
3.4 KiB
LLVM

; RUN: opt < %s -simplifycfg -S | FileCheck %s
%llvm.dbg.anchor.type = type { i32, i32 }
%llvm.dbg.compile_unit.type = type { i32, { }*, i32, i8*, i8*, i8*, i1, i1, i8* }
@llvm.dbg.compile_units = linkonce constant %llvm.dbg.anchor.type { i32 458752, i32 17 }, section "llvm.metadata"
@.str = internal constant [4 x i8] c"a.c\00", section "llvm.metadata" ; <[4 x i8]*> [#uses=1]
@.str1 = internal constant [6 x i8] c"/tmp/\00", section "llvm.metadata" ; <[6 x i8]*> [#uses=1]
@.str2 = internal constant [55 x i8] c"4.2.1 (Based on Apple Inc. build 5636) (LLVM build 00)\00", section "llvm.metadata" ; <[55 x i8]*> [#uses=1]
@llvm.dbg.compile_unit = internal constant %llvm.dbg.compile_unit.type { i32 458769, { }* bitcast (%llvm.dbg.anchor.type* @llvm.dbg.compile_units to { }*), i32 1, i8* getelementptr ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr ([6 x i8]* @.str1, i32 0, i32 0), i8* getelementptr ([55 x i8]* @.str2, i32 0, i32 0), i1 true, i1 false, i8* null }, section "llvm.metadata" ; <%llvm.dbg.compile_unit.type*> [#uses=1]
declare void @llvm.dbg.stoppoint(i32, i32, { }*) nounwind
define i1 @t({ i32, i32 }* %I) {
; CHECK: @t
; CHECK: %off = add i32 %tmp.2.i, -14
; CHECK: %switch = icmp ult i32 %off, 6
entry:
%tmp.1.i = getelementptr { i32, i32 }* %I, i64 0, i32 1 ; <i32*> [#uses=1]
%tmp.2.i = load i32* %tmp.1.i ; <i32> [#uses=6]
%tmp.2 = icmp eq i32 %tmp.2.i, 14 ; <i1> [#uses=1]
br i1 %tmp.2, label %shortcirc_done.4, label %shortcirc_next.0
shortcirc_next.0: ; preds = %entry
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
%tmp.6 = icmp eq i32 %tmp.2.i, 15 ; <i1> [#uses=1]
br i1 %tmp.6, label %shortcirc_done.4, label %shortcirc_next.1
shortcirc_next.1: ; preds = %shortcirc_next.0
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
%tmp.11 = icmp eq i32 %tmp.2.i, 16 ; <i1> [#uses=1]
br i1 %tmp.11, label %shortcirc_done.4, label %shortcirc_next.2
shortcirc_next.2: ; preds = %shortcirc_next.1
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
%tmp.16 = icmp eq i32 %tmp.2.i, 17 ; <i1> [#uses=1]
br i1 %tmp.16, label %shortcirc_done.4, label %shortcirc_next.3
shortcirc_next.3: ; preds = %shortcirc_next.2
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
%tmp.21 = icmp eq i32 %tmp.2.i, 18 ; <i1> [#uses=1]
br i1 %tmp.21, label %shortcirc_done.4, label %shortcirc_next.4
shortcirc_next.4: ; preds = %shortcirc_next.3
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
%tmp.26 = icmp eq i32 %tmp.2.i, 19 ; <i1> [#uses=1]
br label %UnifiedReturnBlock
shortcirc_done.4: ; preds = %shortcirc_next.3, %shortcirc_next.2, %shortcirc_next.1, %shortcirc_next.0, %entry
br label %UnifiedReturnBlock
UnifiedReturnBlock: ; preds = %shortcirc_done.4, %shortcirc_next.4
%UnifiedRetVal = phi i1 [ %tmp.26, %shortcirc_next.4 ], [ true, %shortcirc_done.4 ] ; <i1> [#uses=1]
ret i1 %UnifiedRetVal
}