[llvm-commits] CVS: llvm/test/Regression/Transforms/InstCombine/and-or-and.ll

[Chris Lattner]

Changes in directory llvm/test/Regression/Transforms/InstCombine:

and-or-and.ll added (r1.1)
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Log message:

New testcase for common bitfield manipulation instruction sequences.


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Diffs of the changes:  (+54 -0)

Index: llvm/test/Regression/Transforms/InstCombine/and-or-and.ll
diff -c /dev/null llvm/test/Regression/Transforms/InstCombine/and-or-and.ll:1.1
*** /dev/null	Sat Jan  1 10:14:28 2005
--- llvm/test/Regression/Transforms/InstCombine/and-or-and.ll	Sat Jan  1 10:14:18 2005
***************
*** 0 ****
--- 1,54 ----
+ ; If we have an 'and' of the result of an 'or', and one of the 'or' operands
+ ; cannot have contributed any of the resultant bits, delete the or.  This
+ ; occurs for very common C/C++ code like this:
+ ;
+ ; struct foo { int A : 16; int B : 16; };
+ ; void test(struct foo *F, int X, int Y) {
+ ;        F->A = X; F->B = Y;
+ ; }
+ ;
+ ; Which corresponds to test1.
+ 
+ ; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep 'or '
+ 
+ int %test1(int %X, int %Y) {
+ 	%A = and int %X, 7
+ 	%B = and int %Y, 8
+ 	%C = or int %A, %B
+ 	%D = and int %C, 7  ;; This cannot include any bits from %Y!
+ 	ret int %D
+ }
+ 
+ int %test2(int %X, ubyte %Y) {
+ 	%B = cast ubyte %Y to int
+ 	%C = or int %X, %B
+ 	%D = and int %C, 65536  ;; This cannot include any bits from %Y!
+ 	ret int %D
+ }
+ 
+ int %test3(int %X, int %Y) {
+ 	%B = shl int %Y, ubyte 1
+ 	%C = or int %X, %B
+ 	%D = and int %C, 1  ;; This cannot include any bits from %Y!
+ 	ret int %D
+ }
+ 
+ uint %test4(uint %X, uint %Y) {
+ 	%B = shr uint %Y, ubyte 31
+ 	%C = or uint %X, %B
+ 	%D = and uint %C, 2  ;; This cannot include any bits from %Y!
+ 	ret uint %D
+ }
+ 
+ int %or_test1(int %X, int %Y) {
+ 	%A = and int %X, 1
+ 	%B = or int %A, 1     ;; This cannot include any bits from X!
+ 	ret int %B
+ }
+ 
+ ubyte %or_test2(ubyte %X, ubyte %Y) {
+ 	%A = shl ubyte %X, ubyte 7
+ 	%B = or ubyte %A, 128     ;; This cannot include any bits from X!
+ 	ret ubyte %B
+ }
+