This change handles a another case for generating the bic instruction

when a compile time constant is known.  This occurs when implicitly zero 
extending function arguments from 16 bits to 32 bits.  The 8 bit case doesn't
need to be handled, as the 8 bit constants are encoded directly, thereby
not needing a separate load instruction to form the constant into a register.

<rdar://problem/11481151>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158659 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/ARM/bicZext.ll

@@ -0,0 +1,19 @@
+; RUN: llc %s -o - | FileCheck %s
+; ModuleID = 'bic.c'
+target triple = "thumbv7-apple-ios3.0.0"
+
+define zeroext i16 @foo16(i16 zeroext %f) nounwind readnone optsize ssp {
+entry:
+  ; CHECK: .thumb_func	_foo16
+  ; CHECK: {{bic[^#]*#3}}
+  %and = and i16 %f, -4
+  ret i16 %and
+}
+
+define i32 @foo32(i32 %f) nounwind readnone optsize ssp {
+entry:
+  ; CHECK: .thumb_func	_foo32
+  ; CHECK: {{bic[^#]*#3}}
+  %and = and i32 %f, -4
+  ret i32 %and
+}