From 59ed7d45a6e77dfbe24b880520d828580df62362 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Wed, 24 Oct 2012 19:53:01 +0000
Subject: [PATCH] Fix a miscompilation caused by a typo. When turning a adde
 with negative value into a sbc with a positive number, the immediate should
 be complemented, not negated. Also added a missing pattern for ARM codegen.

rdar://12559385

llvm-svn: 166613
---
 llvm/lib/Target/ARM/ARMInstrInfo.td   | 12 ++++++------
 llvm/lib/Target/ARM/ARMInstrThumb2.td |  2 +-
 llvm/test/CodeGen/ARM/carry.ll        | 13 +++++++++++++
 llvm/test/CodeGen/Thumb2/carry.ll     | 13 +++++++++++++
 4 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMInstrInfo.td b/llvm/lib/Target/ARM/ARMInstrInfo.td
index a78ada0..b193a5c 100644
--- a/llvm/lib/Target/ARM/ARMInstrInfo.td
+++ b/llvm/lib/Target/ARM/ARMInstrInfo.td
@@ -283,15 +283,13 @@ class RegConstraint<string C> {
 //  ARM specific transformation functions and pattern fragments.
 //
 
-// imm_neg_XFORM - Return a imm value packed into the format described for
-// imm_neg defs below.
+// imm_neg_XFORM - Return the negation of an i32 immediate value.
 def imm_neg_XFORM : SDNodeXForm<imm, [{
   return CurDAG->getTargetConstant(-(int)N->getZExtValue(), MVT::i32);
 }]>;
 
-// so_imm_not_XFORM - Return a so_imm value packed into the format described for
-// so_imm_not def below.
-def so_imm_not_XFORM : SDNodeXForm<imm, [{
+// imm_not_XFORM - Return the complement of a i32 immediate value.
+def imm_not_XFORM : SDNodeXForm<imm, [{
   return CurDAG->getTargetConstant(~(int)N->getZExtValue(), MVT::i32);
 }]>;
 
@@ -314,7 +312,7 @@ def so_imm_neg : Operand<i32>, PatLeaf<(imm), [{
 def so_imm_not_asmoperand : AsmOperandClass { let Name = "ARMSOImmNot"; }
 def so_imm_not : Operand<i32>, PatLeaf<(imm), [{
     return ARM_AM::getSOImmVal(~(uint32_t)N->getZExtValue()) != -1;
-  }], so_imm_not_XFORM> {
+  }], imm_not_XFORM> {
   let ParserMatchClass = so_imm_not_asmoperand;
 }
 
@@ -3120,6 +3118,8 @@ def : ARMPat<(ARMaddc GPR:$src, imm0_65535_neg:$imm),
 // for part of the negation.
 def : ARMPat<(ARMadde GPR:$src, so_imm_not:$imm, CPSR),
              (SBCri   GPR:$src, so_imm_not:$imm)>;
+def : ARMPat<(ARMadde GPR:$src, imm0_65535_neg:$imm, CPSR),
+             (SBCrr   GPR:$src, (MOVi16 (imm_not_XFORM imm:$imm)))>;
 
 // Note: These are implemented in C++ code, because they have to generate
 // ADD/SUBrs instructions, which use a complex pattern that a xform function
diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td
index 2c62fdb..1684339 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb2.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td
@@ -1953,7 +1953,7 @@ def : T2Pat<(ARMadde    rGPR:$src, imm0_255_not:$imm, CPSR),
 def : T2Pat<(ARMadde    rGPR:$src, t2_so_imm_not:$imm, CPSR),
             (t2SBCri    rGPR:$src, t2_so_imm_not:$imm)>;
 def : T2Pat<(ARMadde    rGPR:$src, imm0_65535_neg:$imm, CPSR),
-            (t2SBCrr    rGPR:$src, (t2MOVi16 (imm_neg_XFORM imm:$imm)))>;
+            (t2SBCrr    rGPR:$src, (t2MOVi16 (imm_not_XFORM imm:$imm)))>;
 
 // Select Bytes -- for disassembly only
 
diff --git a/llvm/test/CodeGen/ARM/carry.ll b/llvm/test/CodeGen/ARM/carry.ll
index f84774d..bf51cd6 100644
--- a/llvm/test/CodeGen/ARM/carry.ll
+++ b/llvm/test/CodeGen/ARM/carry.ll
@@ -45,3 +45,16 @@ entry:
   %0 = sub nsw i64 0, %x
   ret i64 %0
 }
+
+; rdar://12559385
+define i64 @f5(i32 %vi) {
+entry:
+; CHECK: f5:
+; CHECK: movw [[REG:r[0-9]+]], #36102
+; CHECK: sbc r{{[0-9]+}}, r{{[0-9]+}}, [[REG]]
+    %v0 = zext i32 %vi to i64
+    %v1 = xor i64 %v0, -155057456198619
+    %v4 = add i64 %v1, 155057456198619
+    %v5 = add i64 %v4, %v1
+    ret i64 %v5
+}
diff --git a/llvm/test/CodeGen/Thumb2/carry.ll b/llvm/test/CodeGen/Thumb2/carry.ll
index de6f6e2..85b4370 100644
--- a/llvm/test/CodeGen/Thumb2/carry.ll
+++ b/llvm/test/CodeGen/Thumb2/carry.ll
@@ -20,3 +20,16 @@ entry:
 	%tmp2 = sub i64 %tmp1, %b
 	ret i64 %tmp2
 }
+
+; rdar://12559385
+define i64 @f3(i32 %vi) {
+entry:
+; CHECK: f3:
+; CHECK: movw [[REG:r[0-9]+]], #36102
+; CHECK: sbcs r{{[0-9]+}}, [[REG]]
+    %v0 = zext i32 %vi to i64
+    %v1 = xor i64 %v0, -155057456198619
+    %v4 = add i64 %v1, 155057456198619
+    %v5 = add i64 %v4, %v1
+    ret i64 %v5
+}
-- 
2.7.4