[llvm] r355425 - [X86] Enable 8-bit SHL to convert to LEA

[Craig Topper via llvm-commits]

Author: ctopper
Date: Tue Mar  5 10:37:41 2019
New Revision: 355425

URL: http://llvm.org/viewvc/llvm-project?rev=355425&view=rev
Log:
[X86] Enable 8-bit SHL to convert to LEA

Differential Revision: https://reviews.llvm.org/D58870

Modified:
    llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
    llvm/trunk/lib/Target/X86/X86InstrShiftRotate.td
    llvm/trunk/test/CodeGen/X86/fast-isel-shift.ll
    llvm/trunk/test/CodeGen/X86/mul-constant-i8.ll

Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.cpp?rev=355425&r1=355424&r2=355425&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.cpp Tue Mar  5 10:37:41 2019
@@ -755,6 +755,7 @@ MachineInstr *X86InstrInfo::convertToThr
       BuildMI(*MFI, MBBI, MI.getDebugLoc(), get(Opcode), OutRegLEA);
   switch (MIOpc) {
   default: llvm_unreachable("Unreachable!");
+  case X86::SHL8ri:
   case X86::SHL16ri: {
     unsigned ShAmt = MI.getOperand(2).getImm();
     MIB.addReg(0).addImm(1ULL << ShAmt)
@@ -918,6 +919,9 @@ X86InstrInfo::convertToThreeAddress(Mach
 
     break;
   }
+  case X86::SHL8ri:
+    Is8BitOp = true;
+    LLVM_FALLTHROUGH;
   case X86::SHL16ri: {
     assert(MI.getNumOperands() >= 3 && "Unknown shift instruction!");
     unsigned ShAmt = getTruncatedShiftCount(MI, 2);

Modified: llvm/trunk/lib/Target/X86/X86InstrShiftRotate.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrShiftRotate.td?rev=355425&r1=355424&r2=355425&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrShiftRotate.td (original)
+++ llvm/trunk/lib/Target/X86/X86InstrShiftRotate.td Tue Mar  5 10:37:41 2019
@@ -30,11 +30,11 @@ def SHL64rCL : RI<0xD3, MRM4r, (outs GR6
                   [(set GR64:$dst, (shl GR64:$src1, CL))]>;
 } // Uses = [CL], SchedRW
 
+let isConvertibleToThreeAddress = 1 in {   // Can transform into LEA.
 def SHL8ri   : Ii8<0xC0, MRM4r, (outs GR8 :$dst), (ins GR8 :$src1, u8imm:$src2),
                    "shl{b}\t{$src2, $dst|$dst, $src2}",
                    [(set GR8:$dst, (shl GR8:$src1, (i8 imm:$src2)))]>;
 
-let isConvertibleToThreeAddress = 1 in {   // Can transform into LEA.
 def SHL16ri  : Ii8<0xC1, MRM4r, (outs GR16:$dst), (ins GR16:$src1, u8imm:$src2),
                    "shl{w}\t{$src2, $dst|$dst, $src2}",
                    [(set GR16:$dst, (shl GR16:$src1, (i8 imm:$src2)))]>,

Modified: llvm/trunk/test/CodeGen/X86/fast-isel-shift.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/fast-isel-shift.ll?rev=355425&r1=355424&r2=355425&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/fast-isel-shift.ll (original)
+++ llvm/trunk/test/CodeGen/X86/fast-isel-shift.ll Tue Mar  5 10:37:41 2019
@@ -157,8 +157,8 @@ define i64 @ashr_i64(i64 %a, i64 %b) {
 define i8 @shl_imm1_i8(i8 %a) {
 ; CHECK-LABEL: shl_imm1_i8:
 ; CHECK:       ## %bb.0:
-; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    shlb $1, %al
+; CHECK-NEXT:    ## kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    leal (,%rdi,2), %eax
 ; CHECK-NEXT:    ## kill: def $al killed $al killed $eax
 ; CHECK-NEXT:    retq
   %c = shl i8 %a, 1

Modified: llvm/trunk/test/CodeGen/X86/mul-constant-i8.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/mul-constant-i8.ll?rev=355425&r1=355424&r2=355425&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/mul-constant-i8.ll (original)
+++ llvm/trunk/test/CodeGen/X86/mul-constant-i8.ll Tue Mar  5 10:37:41 2019
@@ -36,8 +36,8 @@ define i8 @test_mul_by_3(i8 %x) {
 define i8 @test_mul_by_4(i8 %x) {
 ; X64-LABEL: test_mul_by_4:
 ; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    shlb $2, %al
+; X64-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-NEXT:    leal (,%rdi,4), %eax
 ; X64-NEXT:    # kill: def $al killed $al killed $eax
 ; X64-NEXT:    retq
   %m = mul i8 %x, 4
@@ -82,8 +82,8 @@ define i8 @test_mul_by_7(i8 %x) {
 define i8 @test_mul_by_8(i8 %x) {
 ; X64-LABEL: test_mul_by_8:
 ; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    shlb $3, %al
+; X64-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-NEXT:    leal (,%rdi,8), %eax
 ; X64-NEXT:    # kill: def $al killed $al killed $eax
 ; X64-NEXT:    retq
   %m = mul i8 %x, 8
@@ -449,8 +449,8 @@ define i8 @test_mul_by_73(i8 %x) {
 define i8 @test_mul_by_520(i8 %x) {
 ; X64-LABEL: test_mul_by_520:
 ; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    shlb $3, %al
+; X64-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-NEXT:    leal (,%rdi,8), %eax
 ; X64-NEXT:    # kill: def $al killed $al killed $eax
 ; X64-NEXT:    retq
   %m = mul i8 %x, 520