Teach 2addr pass to be do more commuting. If both uses of a two-address instruction are killed, but the first operand has a use before and after the def, commute if the second operand does not suffer from the same issue.
%reg1028<def> = EXTRACT_SUBREG %reg1027<kill>, 1                                                                                                                                     
%reg1029<def> = MOV8rr %reg1028                                                                                                                                                      
%reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>                                                                                                                            
insert => %reg1030<def> = MOV8rr %reg1028                                                                                                                                            
%reg1030<def> = ADD8rr %reg1028<kill>, %reg1029<kill>, %EFLAGS<imp-def,dead>                                                                                                         

In this case, it might not be possible to coalesce the second MOV8rr                                                                                                                 
instruction if the first one is coalesced. So it would be profitable to                                                                                                              
commute it:                                                                                                                                                                          
%reg1028<def> = EXTRACT_SUBREG %reg1027<kill>, 1                                                                                                                                     
%reg1029<def> = MOV8rr %reg1028                                                                                                                                                      
%reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>                                                                                                                            
insert => %reg1030<def> = MOV8rr %reg1029                                                                                                                                            
%reg1030<def> = ADD8rr %reg1029<kill>, %reg1028<kill>, %EFLAGS<imp-def,dead>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62954 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/X86/2008-02-22-ReMatBug.ll b/test/CodeGen/X86/2008-02-22-ReMatBug.ll
index f78d526..539fc15 100644
--- a/test/CodeGen/X86/2008-02-22-ReMatBug.ll
+++ b/test/CodeGen/X86/2008-02-22-ReMatBug.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of re-materialization} | grep 3
+; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of re-materialization} | grep 4
 ; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of dead spill slots removed}
 ; rdar://5761454
 
diff --git a/test/CodeGen/X86/2008-07-19-movups-spills.ll b/test/CodeGen/X86/2008-07-19-movups-spills.ll
index ef5c7c5..8800357 100644
--- a/test/CodeGen/X86/2008-07-19-movups-spills.ll
+++ b/test/CodeGen/X86/2008-07-19-movups-spills.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -mtriple=i686-pc-linux -realign-stack=1 -mattr=sse2 | grep movaps | count 76
+; RUN: llvm-as < %s | llc -mtriple=i686-pc-linux -realign-stack=1 -mattr=sse2 | grep movaps | count 75
 ; RUN: llvm-as < %s | llc -mtriple=i686-pc-linux -realign-stack=0 -mattr=sse2 | grep movaps | count 1
 ; PR2539
 
diff --git a/test/CodeGen/X86/pmul.ll b/test/CodeGen/X86/pmul.ll
index 5ee0932..b619411 100644
--- a/test/CodeGen/X86/pmul.ll
+++ b/test/CodeGen/X86/pmul.ll
@@ -1,6 +1,6 @@
 ; RUN: llvm-as < %s | llc -march=x86 -mattr=sse41 -stack-alignment=16 > %t
 ; RUN: grep pmul %t | count 12
-; RUN: grep mov %t | count 19
+; RUN: grep mov %t | count 15
 
 define <4 x i32> @a(<4 x i32> %i) nounwind  {
         %A = mul <4 x i32> %i, < i32 117, i32 117, i32 117, i32 117 >
diff --git a/test/CodeGen/X86/twoaddr-coalesce.ll b/test/CodeGen/X86/twoaddr-coalesce.ll
new file mode 100644
index 0000000..c369d91
--- /dev/null
+++ b/test/CodeGen/X86/twoaddr-coalesce.ll
@@ -0,0 +1,25 @@
+; RUN: llvm-as < %s | llc -march=x86 -join-cross-class-copies -stats |& \
+; RUN:   grep {twoaddrinstr} | grep {Number of instructions aggressively commuted}
+; rdar://6523745
+
+@"\01LC" = internal constant [4 x i8] c"%d\0A\00"		; <[4 x i8]*> [#uses=1]
+
+define i32 @main() nounwind {
+bb1.thread:
+	br label %bb1
+
+bb1:		; preds = %bb1, %bb1.thread
+	%i.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %indvar.next, %bb1 ]		; <i32> [#uses=2]
+	%0 = trunc i32 %i.0.reg2mem.0 to i8		; <i8> [#uses=1]
+	%1 = sdiv i8 %0, 2		; <i8> [#uses=1]
+	%2 = sext i8 %1 to i32		; <i32> [#uses=1]
+	%3 = tail call i32 (i8*, ...)* @printf(i8* getelementptr ([4 x i8]* @"\01LC", i32 0, i32 0), i32 %2) nounwind		; <i32> [#uses=0]
+	%indvar.next = add i32 %i.0.reg2mem.0, 1		; <i32> [#uses=2]
+	%exitcond = icmp eq i32 %indvar.next, 258		; <i1> [#uses=1]
+	br i1 %exitcond, label %bb2, label %bb1
+
+bb2:		; preds = %bb1
+	ret i32 0
+}
+
+declare i32 @printf(i8*, ...) nounwind