From e641e92cb728bb01453d926fa4e69ba8b9ae53bb Mon Sep 17 00:00:00 2001
From: Jim Stichnoth <stichnot@chromium.org>
Date: Mon, 29 Feb 2016 09:54:55 -0800
Subject: [PATCH] Subzero: Fix JumpTable lowering on x86-64.

The problem is that when switch lowering decides to use a JumpTable and the switch variable is i64 on x86-64, the lowering tries to movzx the i64 variable into an i32 variable, and the Movzx ctor asserts.

This happens when translating pnacl-llc.pexe, but luckily it is also triggered in the existing adv-switch.ll test.

BUG= none
R=jpp@chromium.org

Review URL: https://codereview.chromium.org/1743133002 .
---
 src/IceTargetLoweringX86BaseImpl.h         |  7 ++-
 tests_lit/llvm2ice_tests/adv-switch-opt.ll | 71 +++++++++++++++++-------------
 2 files changed, 46 insertions(+), 32 deletions(-)

diff --git a/src/IceTargetLoweringX86BaseImpl.h b/src/IceTargetLoweringX86BaseImpl.h
index a6bc892ff..b056ea4db 100644
--- a/src/IceTargetLoweringX86BaseImpl.h
+++ b/src/IceTargetLoweringX86BaseImpl.h
@@ -5853,7 +5853,12 @@ void TargetX86Base<TraitsType>::lowerCaseCluster(const CaseCluster &Case,
     const Type PointerType = getPointerType();
     if (RangeIndex->getType() != PointerType) {
       Index = makeReg(PointerType);
-      _movzx(Index, RangeIndex);
+      if (RangeIndex->getType() == IceType_i64) {
+        assert(Traits::Is64Bit);
+        _mov(Index, RangeIndex); // trunc
+      } else {
+        _movzx(Index, RangeIndex);
+      }
     } else {
       Index = legalizeToReg(RangeIndex);
     }
diff --git a/tests_lit/llvm2ice_tests/adv-switch-opt.ll b/tests_lit/llvm2ice_tests/adv-switch-opt.ll
index 664e66bea..1942ae96f 100644
--- a/tests_lit/llvm2ice_tests/adv-switch-opt.ll
+++ b/tests_lit/llvm2ice_tests/adv-switch-opt.ll
@@ -1,7 +1,10 @@
 ; This tests the advanced lowering of switch statements. The advanced lowering
 ; uses jump tables, range tests and binary search.
 
-; RUN: %p2i -i %s --filetype=obj --disassemble --args -O2 | FileCheck %s
+; RUN: %p2i -i %s --target=x8632 --filetype=obj --disassemble --args -O2 \
+; RUN:   | FileCheck %s --check-prefix=CHECK --check-prefix=X8632
+; RUN: %p2i -i %s --target=x8664 --filetype=obj --disassemble --args -O2 \
+; RUN:   | FileCheck %s --check-prefix=CHECK --check-prefix=X8664
 
 ; Dense but non-continuous ranges should be converted into a jump table.
 define internal i32 @testJumpTable(i32 %a) {
@@ -32,8 +35,13 @@ sw.epilog:
 ; CHECK: sub [[IND:[^,]+]],0x5b
 ; CHECK-NEXT: cmp [[IND]],0x8
 ; CHECK-NEXT: ja
-; CHECK-NEXT: mov [[TARGET:.*]],DWORD PTR {{\[}}[[IND]]*4+0x0] {{[0-9a-f]+}}: R_386_32 .{{.*}}testJumpTable$jumptable
-; CHECK-NEXT: jmp [[TARGET]]
+; X8632-NEXT: mov [[TARGET:.*]],DWORD PTR {{\[}}[[IND]]*4+0x0] {{[0-9a-f]+}}: R_386_32 .{{.*}}testJumpTable$jumptable
+; X8632-NEXT: jmp [[TARGET]]
+; X8664-NEXT: mov {{.}}[[TARGET:.*]],DWORD PTR {{\[}}[[IND]]*4+0x0] {{[0-9a-f]+}}: R_X86_64_32S .{{.*}}testJumpTable$jumptable
+; X8664-NEXT: jmp {{.}}[[TARGET]]
+; Note: x86-32 may do "mov eax, [...]; jmp eax", whereas x86-64 may do
+; "mov eax, [...]; jmp rax", so we assume the all characters except the first
+; one in the register name will match.
 
 ; Continuous ranges which map to the same target should be grouped and
 ; efficiently tested.
@@ -129,18 +137,18 @@ return:
   ret i32 %retval.0
 }
 ; CHECK-LABEL: testSwitchSmall64
-; CHECK: cmp {{.*}},0x0
-; CHECK-NEXT: jne
-; CHECK-NEXT: cmp {{.*}},0x159
-; CHECK-NEXT: jb
-; CHECK-NEXT: je
-; CHECK-NEXT: cmp {{.*}},0x1c8
-; CHECK-NEXT: je
-; CHECK-NEXT: jmp
-; CHECK-NEXT: cmp {{.*}},0x7b
-; CHECK-NEXT: je
-; CHECK-NEXT: cmp {{.*}},0xea
-; CHECK-NEXT: je
+; X8632: cmp {{.*}},0x0
+; X8632-NEXT: jne
+; X8632-NEXT: cmp {{.*}},0x159
+; X8632-NEXT: jb
+; X8632-NEXT: je
+; X8632-NEXT: cmp {{.*}},0x1c8
+; X8632-NEXT: je
+; X8632-NEXT: jmp
+; X8632-NEXT: cmp {{.*}},0x7b
+; X8632-NEXT: je
+; X8632-NEXT: cmp {{.*}},0xea
+; X8632-NEXT: je
 
 ; Test for correct 64-bit lowering.
 ; TODO(ascull): this should generate better code like the 32-bit version
@@ -170,22 +178,22 @@ return:
   ret i32 %retval.0
 }
 ; CHECK-LABEL: testSwitch64
-; CHECK: cmp {{.*}},0x7b
-; CHECK-NEXT: jne
-; CHECK-NEXT: cmp {{.*}},0x0
-; CHECK-NEXT: je
-; CHECK: cmp {{.*}},0xea
-; CHECK-NEXT: jne
-; CHECK-NEXT: cmp {{.*}},0x0
-; CHECK-NEXT: je
-; CHECK: cmp {{.*}},0x159
-; CHECK-NEXT: jne
-; CHECK-NEXT: cmp {{.*}},0x0
-; CHECK-NEXT: je
-; CHECK: cmp {{.*}},0x34567890
-; CHECK-NEXT: jne
-; CHECK-NEXT: cmp {{.*}},0x12
-; CHECK-NEXT: je
+; X8632: cmp {{.*}},0x7b
+; X8632-NEXT: jne
+; X8632-NEXT: cmp {{.*}},0x0
+; X8632-NEXT: je
+; X8632: cmp {{.*}},0xea
+; X8632-NEXT: jne
+; X8632-NEXT: cmp {{.*}},0x0
+; X8632-NEXT: je
+; X8632: cmp {{.*}},0x159
+; X8632-NEXT: jne
+; X8632-NEXT: cmp {{.*}},0x0
+; X8632-NEXT: je
+; X8632: cmp {{.*}},0x34567890
+; X8632-NEXT: jne
+; X8632-NEXT: cmp {{.*}},0x12
+; X8632-NEXT: je
 
 ; Test for correct 64-bit jump table with UINT64_MAX as one of the values.
 define internal i32 @testJumpTable64(i64 %a) {
@@ -216,3 +224,4 @@ return:
 
 ; TODO(ascull): this should generate a jump table. For now, just make sure it
 ; doesn't crash the compiler.
+; CHECK-LABEL: testJumpTable64
-- 
2.11.0