From d0592d3be68e60a77c0bb98ad4861648e16e467c Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 3 Jan 2010 18:33:18 +0000
Subject: [PATCH] fix PR5930, allowing the asmprinter to emit difference
 between two labels as a truncate.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92455 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/AsmPrinter/AsmPrinter.cpp | 10 +++++++--
 test/CodeGen/X86/x86-64-jumps.ll      | 29 +++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 6b24e24d371..6f26fc402a6 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -819,7 +819,6 @@ void AsmPrinter::EmitConstantValueOnly(const Constant *CV) {
     const TargetData *TD = TM.getTargetData();
     unsigned Opcode = CE->getOpcode();    
     switch (Opcode) {
-    case Instruction::Trunc:
     case Instruction::ZExt:
     case Instruction::SExt:
     case Instruction::FPTrunc:
@@ -865,7 +864,6 @@ void AsmPrinter::EmitConstantValueOnly(const Constant *CV) {
       return EmitConstantValueOnly(Op);
     }
       
-      
     case Instruction::PtrToInt: {
       // Support only foldable casts to/from pointers that can be eliminated by
       // changing the pointer to the appropriately sized integer type.
@@ -887,6 +885,14 @@ void AsmPrinter::EmitConstantValueOnly(const Constant *CV) {
       O << ") & " << S.str() << ')';
       break;
     }
+        
+    case Instruction::Trunc:
+      // We emit the value and depend on the assembler to truncate the generated
+      // expression properly.  This is important for differences between
+      // blockaddress labels.  Since the two labels are in the same function, it
+      // is reasonable to treat their delta as a 32-bit value.
+      return EmitConstantValueOnly(CE->getOperand(0));
+        
     case Instruction::Add:
     case Instruction::Sub:
     case Instruction::And:
diff --git a/test/CodeGen/X86/x86-64-jumps.ll b/test/CodeGen/X86/x86-64-jumps.ll
index 5ed6a23ef87..11b40c89761 100644
--- a/test/CodeGen/X86/x86-64-jumps.ll
+++ b/test/CodeGen/X86/x86-64-jumps.ll
@@ -14,3 +14,32 @@ bb6:                                              ; preds = %entry
   ret i8 2
 }
 
+
+; PR5930 - Trunc of block address differences.
+@test.array = internal constant [3 x i32] [i32 trunc (i64 sub (i64 ptrtoint (i8* blockaddress(@test2, %foo) to i64), i64 ptrtoint (i8* blockaddress(@test2, %foo) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (i8* blockaddress(@test2, %bar) to i64), i64 ptrtoint (i8* blockaddress(@test2, %foo) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (i8* blockaddress(@test2, %hack) to i64), i64 ptrtoint (i8* blockaddress(@test2, %foo) to i64)) to i32)] ; <[3 x i32]*> [#uses=1]
+
+define void @test2(i32 %i) nounwind ssp {
+entry:
+  %i.addr = alloca i32                            ; <i32*> [#uses=2]
+  store i32 %i, i32* %i.addr
+  %tmp = load i32* %i.addr                        ; <i32> [#uses=1]
+  %idxprom = sext i32 %tmp to i64                 ; <i64> [#uses=1]
+  %arrayidx = getelementptr inbounds i32* getelementptr inbounds ([3 x i32]* @test.array, i32 0, i32 0), i64 %idxprom ; <i32*> [#uses=1]
+  %tmp1 = load i32* %arrayidx                     ; <i32> [#uses=1]
+  %idx.ext = sext i32 %tmp1 to i64                ; <i64> [#uses=1]
+  %add.ptr = getelementptr i8* blockaddress(@test2, %foo), i64 %idx.ext ; <i8*> [#uses=1]
+  br label %indirectgoto
+
+foo:                                              ; preds = %indirectgoto, %indirectgoto, %indirectgoto, %indirectgoto, %indirectgoto
+  br label %bar
+
+bar:                                              ; preds = %foo, %indirectgoto
+  br label %hack
+
+hack:                                             ; preds = %bar, %indirectgoto
+  ret void
+
+indirectgoto:                                     ; preds = %entry
+  %indirect.goto.dest = phi i8* [ %add.ptr, %entry ] ; <i8*> [#uses=1]
+  indirectbr i8* %indirect.goto.dest, [label %foo, label %foo, label %bar, label %foo, label %hack, label %foo, label %foo]
+}
-- 
2.34.1