From 68081ee62375a1d900d46f969e38330f14fb8775 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 6 Mar 2014 12:23:34 -0800
Subject: Implement integer promotion for urem, udiv, srem, and sdiv

The optimizer sometimes thinks it's beneficial to truncate all manner of
i64 operators to narrower types, even when still wider than the platform's
widest legal type.
---
 lib/Transforms/NaCl/PromoteIntegers.cpp  | 30 ++++++++++++++---
 test/Transforms/NaCl/promote-integers.ll | 56 ++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 5 deletions(-)

diff --git a/lib/Transforms/NaCl/PromoteIntegers.cpp b/lib/Transforms/NaCl/PromoteIntegers.cpp
index af34faa7e5..ed374da3dd 100644
--- a/lib/Transforms/NaCl/PromoteIntegers.cpp
+++ b/lib/Transforms/NaCl/PromoteIntegers.cpp
@@ -577,18 +577,38 @@ void PromoteIntegers::convertInstruction(Instruction *Inst, ConversionState &Sta
             State.getConverted(Binop->getOperand(1)),
             Binop->getName() + ".result", Binop), Binop);
         break;
+      // XXX EMSCRIPTEN: Implement {U,S}{Div,Rem}
+      case Instruction::UDiv:
+      case Instruction::URem:
+        NewInst = CopyDebug(BinaryOperator::Create(
+            Binop->getOpcode(),
+            getClearConverted(Binop->getOperand(0),
+                              Binop,
+                              State),
+            getClearConverted(Binop->getOperand(1),
+                              Binop,
+                              State),
+            Binop->getName() + ".result", Binop), Binop);
+         break;
+      case Instruction::SDiv:
+      case Instruction::SRem:
+        NewInst = CopyDebug(BinaryOperator::Create(
+            Binop->getOpcode(),
+            getSignExtend(State.getConverted(Binop->getOperand(0)),
+                          Binop->getOperand(0),
+                          Binop),
+            getSignExtend(State.getConverted(Binop->getOperand(1)),
+                          Binop->getOperand(0),
+                          Binop),
+            Binop->getName() + ".result", Binop), Binop);
+         break;
       case Instruction::FAdd:
       case Instruction::FSub:
       case Instruction::FMul:
-      case Instruction::UDiv:
-      case Instruction::SDiv:
       case Instruction::FDiv:
-      case Instruction::URem:
-      case Instruction::SRem:
       case Instruction::FRem:
       case Instruction::BinaryOpsEnd:
         // We should not see FP operators here.
-        // We don't handle div.
         errs() << *Inst << "\n";
         llvm_unreachable("Cannot handle binary operator");
         break;
diff --git a/test/Transforms/NaCl/promote-integers.ll b/test/Transforms/NaCl/promote-integers.ll
index 7c010be32b..baab0822cd 100644
--- a/test/Transforms/NaCl/promote-integers.ll
+++ b/test/Transforms/NaCl/promote-integers.ll
@@ -228,6 +228,62 @@ define void @ashr1(i16 %a) {
   ret void
 }
 
+; CHECK: @udiv1
+define void @udiv1(i32 %a, i32 %b) {
+; CHECK-NEXT: %a33 = zext i32 %a to i64
+  %a33 = zext i32 %a to i33
+; CHECK-NEXT: %b33 = zext i32 %b to i64
+  %b33 = zext i32 %b to i33
+; CHECK-NEXT: %a33.clear = and i64 %a33, 8589934591
+; CHECK-NEXT: %b33.clear = and i64 %b33, 8589934591
+; CHECK-NEXT: %result = udiv i64 %a33.clear, %b33.clear
+  %result = udiv i33 %a33, %b33
+  ret void
+}
+
+; CHECK: @sdiv1
+define void @sdiv1(i32 %a, i32 %b) {
+; CHECK-NEXT: %a33 = sext i32 %a to i64
+  %a33 = sext i32 %a to i33
+; CHECK-NEXT: %b33 = sext i32 %b to i64
+; CHECK-NEXT: %a33.getsign = shl i64 %a33, 31
+; CHECK-NEXT: %a33.signed = ashr i64 %a33.getsign, 31
+; CHECK-NEXT: %b33.getsign = shl i64 %b33, 31
+; CHECK-NEXT: %b33.signed = ashr i64 %b33.getsign, 31
+  %b33 = sext i32 %b to i33
+; CHECK-NEXT: %result = sdiv i64 %a33.signed, %b33.signed
+  %result = sdiv i33 %a33, %b33
+  ret void
+}
+
+; CHECK: @urem1
+define void @urem1(i32 %a, i32 %b) {
+; CHECK-NEXT: %a33 = zext i32 %a to i64
+  %a33 = zext i32 %a to i33
+; CHECK-NEXT: %b33 = zext i32 %b to i64
+; CHECK-NEXT: %a33.clear = and i64 %a33, 8589934591
+; CHECK-NEXT: %b33.clear = and i64 %b33, 8589934591
+  %b33 = zext i32 %b to i33
+; CHECK-NEXT: %result = urem i64 %a33.clear, %b33.clear
+  %result = urem i33 %a33, %b33
+  ret void
+}
+
+; CHECK: @srem1
+define void @srem1(i32 %a, i32 %b) {
+; CHECK-NEXT: %a33 = sext i32 %a to i64
+  %a33 = sext i32 %a to i33
+; CHECK-NEXT: %b33 = sext i32 %b to i64
+; CHECK-NEXT: %a33.getsign = shl i64 %a33, 31
+; CHECK-NEXT: %a33.signed = ashr i64 %a33.getsign, 31
+; CHECK-NEXT: %b33.getsign = shl i64 %b33, 31
+; CHECK-NEXT: %b33.signed = ashr i64 %b33.getsign, 31
+  %b33 = sext i32 %b to i33
+; CHECK-NEXT: %result = srem i64 %a33.signed, %b33.signed
+  %result = srem i33 %a33, %b33
+  ret void
+}
+
 ; CHECK: @phi_icmp
 define void @phi_icmp(i32 %a) {
 entry:
-- 
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