When converting a test to a cmp to fold a load, use the cmp that has an

8-bit immediate field rather than one with a wider immediate field.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104064 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index fb3cbed33672ed6fb3d922e7995e211fb3bfcd26..d4ef62bece704028dfdcc406f14aba8d61b6fd2c 100644 (file)
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -2529,9 +2529,9 @@ MachineInstr* X86InstrInfo::foldMemoryOperandImpl(MachineFunction &MF,
     switch (MI->getOpcode()) {
     default: return NULL;
     case X86::TEST8rr:  NewOpc = X86::CMP8ri; RCSize = 1; break;
-    case X86::TEST16rr: NewOpc = X86::CMP16ri; RCSize = 2; break;
-    case X86::TEST32rr: NewOpc = X86::CMP32ri; RCSize = 4; break;
-    case X86::TEST64rr: NewOpc = X86::CMP64ri32; RCSize = 8; break;
+    case X86::TEST16rr: NewOpc = X86::CMP16ri8; RCSize = 2; break;
+    case X86::TEST32rr: NewOpc = X86::CMP32ri8; RCSize = 4; break;
+    case X86::TEST64rr: NewOpc = X86::CMP64ri8; RCSize = 8; break;
     }
     // Check if it's safe to fold the load. If the size of the object is
     // narrower than the load width, then it's not.

diff --git a/test/CodeGen/X86/mcinst-lowering-cmp0.ll b/test/CodeGen/X86/mcinst-lowering-cmp0.ll
new file mode 100644 (file)
index 0000000..756be1f
--- /dev/null
+++ b/test/CodeGen/X86/mcinst-lowering-cmp0.ll
@@ -0,0 +1,68 @@
+; RUN: llc --show-mc-encoding -relocation-model=pic -disable-fp-elim -O3 < %s | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
+target triple = "i386-apple-darwin10.0.0"
+
+%struct.NSConstantString = type { i32*, i32, i8*, i32 }
+%struct._objc_module = type { i32, i32, i8*, %struct._objc_symtab* }
+%struct._objc_symtab = type { i32, i8*, i16, i16, [0 x i8*] }
+
+@"\01L_OBJC_IMAGE_INFO" = internal constant [2 x i32] [i32 0, i32 16], section "__OBJC, __image_info,regular" ; <[2 x i32]*> [#uses=1]
+@"\01L_OBJC_METH_VAR_NAME_" = internal global [4 x i8] c"foo\00", section "__TEXT,__cstring,cstring_literals", align 1 ; <[4 x i8]*> [#uses=1]
+@"\01L_OBJC_SELECTOR_REFERENCES_" = internal global i8* getelementptr inbounds ([4 x i8]* @"\01L_OBJC_METH_VAR_NAME_", i32 0, i32 0), section "__OBJC,__message_refs,literal_pointers,no_dead_strip", align 4 ; <i8**> [#uses=3]
+@__CFConstantStringClassReference = external global [0 x i32] ; <[0 x i32]*> [#uses=1]
+@.str = private constant [3 x i8] c"||\00"        ; <[3 x i8]*> [#uses=1]
+@_unnamed_cfstring_ = private constant %struct.NSConstantString { i32* getelementptr inbounds ([0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr inbounds ([3 x i8]* @.str, i32 0, i32 0), i32 2 }, section "__DATA,__cfstring" ; <%struct.NSConstantString*> [#uses=1]
+@"\01L_OBJC_METH_VAR_NAME_1" = internal global [5 x i8] c"baz:\00", section "__TEXT,__cstring,cstring_literals", align 1 ; <[5 x i8]*> [#uses=1]
+@"\01L_OBJC_SELECTOR_REFERENCES_2" = internal global i8* getelementptr inbounds ([5 x i8]* @"\01L_OBJC_METH_VAR_NAME_1", i32 0, i32 0), section "__OBJC,__message_refs,literal_pointers,no_dead_strip", align 4 ; <i8**> [#uses=2]
+@"\01L_OBJC_METH_VAR_NAME_3" = internal global [4 x i8] c"bar\00", section "__TEXT,__cstring,cstring_literals", align 1 ; <[4 x i8]*> [#uses=1]
+@"\01L_OBJC_SELECTOR_REFERENCES_4" = internal global i8* getelementptr inbounds ([4 x i8]* @"\01L_OBJC_METH_VAR_NAME_3", i32 0, i32 0), section "__OBJC,__message_refs,literal_pointers,no_dead_strip", align 4 ; <i8**> [#uses=2]
+@"\01L_OBJC_CLASS_NAME_" = internal global [1 x i8] zeroinitializer, section "__TEXT,__cstring,cstring_literals", align 1 ; <[1 x i8]*> [#uses=1]
+@"\01L_OBJC_MODULES" = internal global %struct._objc_module { i32 7, i32 16, i8* getelementptr inbounds ([1 x i8]* @"\01L_OBJC_CLASS_NAME_", i32 0, i32 0), %struct._objc_symtab* null }, section "__OBJC,__module_info,regular,no_dead_strip", align 4 ; <%struct._objc_module*> [#uses=1]
+@llvm.used = appending global [9 x i8*] [i8* bitcast ([2 x i32]* @"\01L_OBJC_IMAGE_INFO" to i8*), i8* getelementptr inbounds ([4 x i8]* @"\01L_OBJC_METH_VAR_NAME_", i32 0, i32 0), i8* bitcast (i8** @"\01L_OBJC_SELECTOR_REFERENCES_" to i8*), i8* getelementptr inbounds ([5 x i8]* @"\01L_OBJC_METH_VAR_NAME_1", i32 0, i32 0), i8* bitcast (i8** @"\01L_OBJC_SELECTOR_REFERENCES_2" to i8*), i8* getelementptr inbounds ([4 x i8]* @"\01L_OBJC_METH_VAR_NAME_3", i32 0, i32 0), i8* bitcast (i8** @"\01L_OBJC_SELECTOR_REFERENCES_4" to i8*), i8* getelementptr inbounds ([1 x i8]* @"\01L_OBJC_CLASS_NAME_", i32 0, i32 0), i8* bitcast (%struct._objc_module* @"\01L_OBJC_MODULES" to i8*)], section "llvm.metadata" ; <[9 x i8*]*> [#uses=0]
+
+define void @f0(i8* nocapture %a, i8* nocapture %b) nounwind optsize ssp {
+entry:
+  %call = tail call i32 (...)* @get_name() nounwind optsize ; <i32> [#uses=2]
+  %conv = inttoptr i32 %call to i8*               ; <i8*> [#uses=1]
+  %call1 = tail call i32 (...)* @get_dict() nounwind optsize ; <i32> [#uses=2]
+  %conv2 = inttoptr i32 %call1 to i8*             ; <i8*> [#uses=2]
+
+; Check that we lower to the short form of cmpl, which has an 8-bit immediate.
+;
+; CHECK: cmpl  $0, -16(%ebp)           ## 4-byte Folded Reload
+; CHECK:                               ## encoding: [0x83,0x7d,0xf0,0x00]
+; rdar://7999130
+  %cmp = icmp eq i32 %call1, 0                    ; <i1> [#uses=1]
+  br i1 %cmp, label %if.end, label %if.then
+
+if.then:                                          ; preds = %entry
+  %tmp5 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_" ; <i8*> [#uses=1]
+  %call6 = tail call i8* (i8*, i8*, ...)* @objc_msgSend(i8* %conv2, i8* %tmp5) nounwind optsize ; <i8*> [#uses=1]
+  %tmp7 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_2" ; <i8*> [#uses=1]
+  %call820 = tail call i8* (i8*, i8*, ...)* @objc_msgSend(i8* %call6, i8* %tmp7, i8* bitcast (%struct.NSConstantString* @_unnamed_cfstring_ to i8*)) nounwind optsize ; <i8*> [#uses=0]
+  br label %if.end
+
+if.end:                                           ; preds = %entry, %if.then
+  %tmp10 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_" ; <i8*> [#uses=1]
+  %call11 = tail call i8* (i8*, i8*, ...)* @objc_msgSend(i8* %conv2, i8* %tmp10) nounwind optsize ; <i8*> [#uses=1]
+  %tmp12 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_4" ; <i8*> [#uses=1]
+  %call13 = tail call i8* (i8*, i8*, ...)* @objc_msgSend(i8* %call11, i8* %tmp12) nounwind optsize ; <i8*> [#uses=0]
+  %cmp15 = icmp eq i32 %call, 0                   ; <i1> [#uses=1]
+  br i1 %cmp15, label %if.end19, label %if.then17
+
+if.then17:                                        ; preds = %if.end
+  tail call void (...)* @f1(i8* %conv) nounwind optsize
+  ret void
+
+if.end19:                                         ; preds = %if.end
+  ret void
+}
+
+declare i32 @get_name(...) optsize
+
+declare i32 @get_dict(...) optsize
+
+declare i8* @objc_msgSend(i8*, i8*, ...)
+
+declare void @f1(...) optsize