When CodeGen'ing unoptimized code, there may be unfolded constant expressions

in global initializers. Instead of aborting, attempt to fold them on the
spot. If folding succeeds, emit the folded expression instead.

This fixes PR6255.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95583 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 313269115900e6906b8150a4ef1611941a00c465..5f730e03c6f5181a4fa839c81d27c5d34a943126 100644 (file)
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -25,6 +25,7 @@
 #include "llvm/CodeGen/MachineJumpTableInfo.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/DebugInfo.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCExpr.h"
@@ -887,15 +888,16 @@ static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
   }
   
   switch (CE->getOpcode()) {
-  case Instruction::ZExt:
-  case Instruction::SExt:
-  case Instruction::FPTrunc:
-  case Instruction::FPExt:
-  case Instruction::UIToFP:
-  case Instruction::SIToFP:
-  case Instruction::FPToUI:
-  case Instruction::FPToSI:
-  default: llvm_unreachable("FIXME: Don't support this constant cast expr");
+  default:
+    // If the code isn't optimized, there may be outstanding folding
+    // opportunities. Attempt to fold the expression using TargetData as a
+    // last resort before giving up.
+    if (Constant *C = ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
+      return LowerConstant(C, AP);
+#ifndef NDEBUG
+    CE->dump();
+#endif
+    llvm_unreachable("FIXME: Don't support this constant expr");
   case Instruction::GetElementPtr: {
     const TargetData &TD = *AP.TM.getTargetData();
     // Generate a symbolic expression for the byte address

diff --git a/test/CodeGen/X86/ptrtoint-constexpr.ll b/test/CodeGen/X86/ptrtoint-constexpr.ll
index 7e33e7916c89c8307fe2753f427a2c7ffbc46671..dd9790568abee3e01fcebb6741fc972b01505577 100644 (file)
--- a/test/CodeGen/X86/ptrtoint-constexpr.ll
+++ b/test/CodeGen/X86/ptrtoint-constexpr.ll
@@ -6,3 +6,9 @@
 ; CHECK: .quad r&4294967295
 
 @r = global %union.x { i64 ptrtoint (%union.x* @r to i64) }, align 4
+
+; CHECK:       .globl x
+; CHECK: x:
+; CHECK: .quad 3
+
+@x = global i64 mul (i64 3, i64 ptrtoint (i2* getelementptr (i2* null, i64 1) to i64))