From dd52bf2ed806229732115400b2a060204f24dea3 Mon Sep 17 00:00:00 2001
From: Joel Jones <joel_k_jones@apple.com>
Date: Mon, 4 Jun 2012 23:38:57 +0000
Subject: [PATCH] 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.

<rdar://problem/11481151>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157966 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMInstrThumb2.td | 24 ++++++++++++++++++++++++
 test/CodeGen/ARM/bicNoZext.ll    | 19 +++++++++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 test/CodeGen/ARM/bicNoZext.ll

diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index c309f84b58b..f7b8a835f79 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -62,6 +62,14 @@ def t2_so_imm_neg_XFORM : SDNodeXForm<imm, [{
   return CurDAG->getTargetConstant(-((int)N->getZExtValue()), MVT::i32);
 }]>;
 
+// so_imm_not_sext_XFORM - Return a so_imm value packed into the format
+// described for so_imm_not_sext def below.
+def t2_so_imm_not_sext_XFORM : SDNodeXForm<imm, [{
+  APInt apIntN = N->getAPIntValue();
+  unsigned N16bitSignExt = apIntN.trunc(16).sext(32).getZExtValue();
+  return CurDAG->getTargetConstant(~N16bitSignExt, MVT::i32);
+}]>;
+
 // t2_so_imm - Match a 32-bit immediate operand, which is an
 // 8-bit immediate rotated by an arbitrary number of bits, or an 8-bit
 // immediate splatted into multiple bytes of the word.
@@ -86,6 +94,17 @@ def t2_so_imm_not : Operand<i32>, PatLeaf<(imm), [{
   let ParserMatchClass = t2_so_imm_not_asmoperand;
 }
 
+// t2_so_imm_not_sext - Match an immediate that when zero-extended
+// from 16-bits to 32-bits is a complement of a t2_so_imm.
+def t2_so_imm_not_sext : Operand<i32>, PatLeaf<(imm), [{
+    APInt apIntN = N->getAPIntValue();
+    if (!apIntN.isIntN(16)) return false;
+    unsigned N16bitSignExt = apIntN.trunc(16).sext(32).getZExtValue();
+    return ARM_AM::getT2SOImmVal(~N16bitSignExt) != -1;
+  }], t2_so_imm_not_sext_XFORM> {
+  let ParserMatchClass = t2_so_imm_not_asmoperand;
+}
+
 // t2_so_imm_neg - Match an immediate that is a negation of a t2_so_imm.
 def t2_so_imm_neg_asmoperand : AsmOperandClass { let Name = "T2SOImmNeg"; }
 def t2_so_imm_neg : Operand<i32>, PatLeaf<(imm), [{
@@ -2332,6 +2351,11 @@ let AddedComplexity = 1 in
 def : T2Pat<(and     rGPR:$src, t2_so_imm_not:$imm),
             (t2BICri rGPR:$src, t2_so_imm_not:$imm)>;
 
+// so_imm_not_sext is needed instead of so_imm_not, as the value of imm
+// will match the original bitWidth for $src.
+def : T2Pat<(and rGPR:$src, t2_so_imm_not_sext:$imm),
+            (t2BICri rGPR:$src, t2_so_imm_not_sext:$imm)>;
+
 // FIXME: Disable this pattern on Darwin to workaround an assembler bug.
 def : T2Pat<(or      rGPR:$src, t2_so_imm_not:$imm),
             (t2ORNri rGPR:$src, t2_so_imm_not:$imm)>,
diff --git a/test/CodeGen/ARM/bicNoZext.ll b/test/CodeGen/ARM/bicNoZext.ll
new file mode 100644
index 00000000000..cf4b7ba0e04
--- /dev/null
+++ b/test/CodeGen/ARM/bicNoZext.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
+}