From: Craig Topper <craig.topper@intel.com>
Date: Thu, 30 Nov 2017 20:15:31 +0000 (+0000)
Subject: [X86] Promote i8 CTPOP to i32 instead of i16 when we have the POPCNT instruction.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d6aaba398813dfb5255dab9c6909187a058d90e6;p=llvm

[X86] Promote i8 CTPOP to i32 instead of i16 when we have the POPCNT instruction.

The 32-bit version is shorter to encode and the zext we emit for the promotion is likely going to be a 32-bit zero extend anyway.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319468 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 54523d7233e..45246421bab 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -399,7 +399,7 @@ X86TargetLowering::X86TargetLowering(const X86TargetMachine &TM,
   setTruncStoreAction(MVT::f80, MVT::f16, Expand);
 
   if (Subtarget.hasPOPCNT()) {
-    setOperationAction(ISD::CTPOP          , MVT::i8   , Promote);
+    setOperationPromotedToType(ISD::CTPOP, MVT::i8, MVT::i32);
   } else {
     setOperationAction(ISD::CTPOP          , MVT::i8   , Expand);
     setOperationAction(ISD::CTPOP          , MVT::i16  , Expand);
diff --git a/test/CodeGen/X86/ctpop-combine.ll b/test/CodeGen/X86/ctpop-combine.ll
index 87e43a1e109..955b8a14410 100644
--- a/test/CodeGen/X86/ctpop-combine.ll
+++ b/test/CodeGen/X86/ctpop-combine.ll
@@ -54,8 +54,8 @@ define i8 @test4(i8 %x) nounwind readnone {
 ; CHECK-LABEL: test4:
 ; CHECK:       # BB#0:
 ; CHECK-NEXT:    andl $127, %edi
-; CHECK-NEXT:    popcntw %di, %ax
-; CHECK-NEXT:    # kill: %al<def> %al<kill> %ax<kill>
+; CHECK-NEXT:    popcntl %edi, %eax
+; CHECK-NEXT:    # kill: %al<def> %al<kill> %eax<kill>
 ; CHECK-NEXT:    retq
   %x2 = and i8 %x, 127
   %count = tail call i8 @llvm.ctpop.i8(i8 %x2)
diff --git a/test/CodeGen/X86/popcnt.ll b/test/CodeGen/X86/popcnt.ll
index a4ed30e7bd9..d11f714c3e7 100644
--- a/test/CodeGen/X86/popcnt.ll
+++ b/test/CodeGen/X86/popcnt.ll
@@ -43,15 +43,15 @@ define i8 @cnt8(i8 %x) nounwind readnone {
 ; X32-POPCNT-LABEL: cnt8:
 ; X32-POPCNT:       # BB#0:
 ; X32-POPCNT-NEXT:    movzbl {{[0-9]+}}(%esp), %eax
-; X32-POPCNT-NEXT:    popcntw %ax, %ax
-; X32-POPCNT-NEXT:    # kill: %al<def> %al<kill> %ax<kill>
+; X32-POPCNT-NEXT:    popcntl %eax, %eax
+; X32-POPCNT-NEXT:    # kill: %al<def> %al<kill> %eax<kill>
 ; X32-POPCNT-NEXT:    retl
 ;
 ; X64-POPCNT-LABEL: cnt8:
 ; X64-POPCNT:       # BB#0:
 ; X64-POPCNT-NEXT:    movzbl %dil, %eax
-; X64-POPCNT-NEXT:    popcntw %ax, %ax
-; X64-POPCNT-NEXT:    # kill: %al<def> %al<kill> %ax<kill>
+; X64-POPCNT-NEXT:    popcntl %eax, %eax
+; X64-POPCNT-NEXT:    # kill: %al<def> %al<kill> %eax<kill>
 ; X64-POPCNT-NEXT:    retq
   %cnt = tail call i8 @llvm.ctpop.i8(i8 %x)
   ret i8 %cnt