From 029e84caf411eeaf5a458af0a987708500ec1ab5 Mon Sep 17 00:00:00 2001
From: Dan Gohman <dan433584@gmail.com>
Date: Thu, 10 Dec 2015 00:37:51 +0000
Subject: [PATCH] PeepholeOptimizer: Ignore dead implicit defs

Target-specific instructions may have uninteresting physreg clobbers,
for target-specific reasons. The peephole pass doesn't need to concern
itself with such defs, as long as they're implicit and marked as dead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255182 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/PeepholeOptimizer.cpp |  6 ++++++
 test/CodeGen/WebAssembly/conv.ll  | 28 ++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/lib/CodeGen/PeepholeOptimizer.cpp b/lib/CodeGen/PeepholeOptimizer.cpp
index 0fabc40b64e..f861edf7da2 100644
--- a/lib/CodeGen/PeepholeOptimizer.cpp
+++ b/lib/CodeGen/PeepholeOptimizer.cpp
@@ -1343,6 +1343,9 @@ bool PeepholeOptimizer::foldImmediate(MachineInstr *MI, MachineBasicBlock *MBB,
     MachineOperand &MO = MI->getOperand(i);
     if (!MO.isReg() || MO.isDef())
       continue;
+    // Ignore dead implicit defs.
+    if (MO.isImplicit() && MO.isDead())
+      continue;
     unsigned Reg = MO.getReg();
     if (!TargetRegisterInfo::isVirtualRegister(Reg))
       continue;
@@ -1703,6 +1706,9 @@ ValueTrackerResult ValueTracker::getNextSourceFromBitcast() {
     const MachineOperand &MO = Def->getOperand(OpIdx);
     if (!MO.isReg() || !MO.getReg())
       continue;
+    // Ignore dead implicit defs.
+    if (MO.isImplicit() && MO.isDead())
+      continue;
     assert(!MO.isDef() && "We should have skipped all the definitions by now");
     if (SrcIdx != EndOpIdx)
       // Multiple sources?
diff --git a/test/CodeGen/WebAssembly/conv.ll b/test/CodeGen/WebAssembly/conv.ll
index 76fa38090a1..e1acaca2c9e 100644
--- a/test/CodeGen/WebAssembly/conv.ll
+++ b/test/CodeGen/WebAssembly/conv.ll
@@ -225,3 +225,31 @@ define i64 @anyext(i32 %x) {
     %w = shl i64 %y, 32
     ret i64 %w
 }
+
+; CHECK-LABEL: bitcast_i32_to_float:
+; CHECK: f32.reinterpret/i32   $push0=, $0{{$}}
+define float @bitcast_i32_to_float(i32 %a) {
+  %t = bitcast i32 %a to float
+  ret float %t
+}
+
+; CHECK-LABEL: bitcast_float_to_i32:
+; CHECK: i32.reinterpret/f32   $push0=, $0{{$}}
+define i32 @bitcast_float_to_i32(float %a) {
+  %t = bitcast float %a to i32
+  ret i32 %t
+}
+
+; CHECK-LABEL: bitcast_i64_to_double:
+; CHECK: f64.reinterpret/i64   $push0=, $0{{$}}
+define double @bitcast_i64_to_double(i64 %a) {
+  %t = bitcast i64 %a to double
+  ret double %t
+}
+
+; CHECK-LABEL: bitcast_double_to_i64:
+; CHECK: i64.reinterpret/f64   $push0=, $0{{$}}
+define i64 @bitcast_double_to_i64(double %a) {
+  %t = bitcast double %a to i64
+  ret i64 %t
+}
-- 
2.11.0