[X86] Change multiply by 26 to use two multiplies by 5 and an add instead of multiply...

Same number of operations, but ending in an add is friendlier due to it being commutable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337869 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 12f6d409a6030c0a62e3fa241ba547bec687de69..352e81700077359a61cb82fb1c4390f08ebefac0 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -33698,10 +33698,10 @@ static SDValue combineMulSpecial(uint64_t MulAmt, SDNode *N, SelectionDAG &DAG,
     return Result;
   };
 
-  auto combineMulMulAddOrSub = [&](bool isAdd) {
+  auto combineMulMulAddOrSub = [&](int Mul1, int Mul2, bool isAdd) {
     SDValue Result = DAG.getNode(X86ISD::MUL_IMM, DL, VT, N->getOperand(0),
-                                 DAG.getConstant(9, DL, VT));
-    Result = DAG.getNode(ISD::MUL, DL, VT, Result, DAG.getConstant(3, DL, VT));
+                                 DAG.getConstant(Mul1, DL, VT));
+    Result = DAG.getNode(ISD::MUL, DL, VT, Result, DAG.getConstant(Mul2, DL, VT));
     Result = DAG.getNode(isAdd ? ISD::ADD : ISD::SUB, DL, VT, Result,
                          N->getOperand(0));
     return Result;
@@ -33730,15 +33730,15 @@ static SDValue combineMulSpecial(uint64_t MulAmt, SDNode *N, SelectionDAG &DAG,
     // mul x, 23 => sub ((shl (mul x, 3), 3), x)
     return combineMulShlAddOrSub(3, 3, /*isAdd*/ false);
   case 26:
-    // mul x, 26 => sub ((mul (mul x, 9), 3), x)
-    return combineMulMulAddOrSub(/*isAdd*/ false);
+    // mul x, 26 => add ((mul (mul x, 5), 5), x)
+    return combineMulMulAddOrSub(5, 5, /*isAdd*/ true);
   case 28:
     // mul x, 28 => add ((mul (mul x, 9), 3), x)
-    return combineMulMulAddOrSub(/*isAdd*/ true);
+    return combineMulMulAddOrSub(9, 3, /*isAdd*/ true);
   case 29:
     // mul x, 29 => add (add ((mul (mul x, 9), 3), x), x)
     return DAG.getNode(ISD::ADD, DL, VT, N->getOperand(0),
-                       combineMulMulAddOrSub(/*isAdd*/ true));
+                       combineMulMulAddOrSub(9, 3, /*isAdd*/ true));
   }
   return SDValue();
 }

diff --git a/test/CodeGen/X86/mul-constant-i16.ll b/test/CodeGen/X86/mul-constant-i16.ll
index 044e7cebf5daaf4892687229883a708e0c085bb8..83980f9fa1f593eac5e50a547cf8a10d2d33e252 100644 (file)
--- a/test/CodeGen/X86/mul-constant-i16.ll
+++ b/test/CodeGen/X86/mul-constant-i16.ll
@@ -494,18 +494,18 @@ define i16 @test_mul_by_26(i16 %x) {
 ; X86-LABEL: test_mul_by_26:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    leal (%ecx,%ecx,8), %eax
-; X86-NEXT:    leal (%eax,%eax,2), %eax
-; X86-NEXT:    subl %ecx, %eax
+; X86-NEXT:    leal (%ecx,%ecx,4), %eax
+; X86-NEXT:    leal (%eax,%eax,4), %eax
+; X86-NEXT:    addl %ecx, %eax
 ; X86-NEXT:    # kill: def $ax killed $ax killed $eax
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: test_mul_by_26:
 ; X64:       # %bb.0:
 ; X64-NEXT:    # kill: def $edi killed $edi def $rdi
-; X64-NEXT:    leal (%rdi,%rdi,8), %eax
-; X64-NEXT:    leal (%rax,%rax,2), %eax
-; X64-NEXT:    subl %edi, %eax
+; X64-NEXT:    leal (%rdi,%rdi,4), %eax
+; X64-NEXT:    leal (%rax,%rax,4), %eax
+; X64-NEXT:    addl %edi, %eax
 ; X64-NEXT:    # kill: def $ax killed $ax killed $eax
 ; X64-NEXT:    retq
   %mul = mul nsw i16 %x, 26

diff --git a/test/CodeGen/X86/mul-constant-i32.ll b/test/CodeGen/X86/mul-constant-i32.ll
index 6b2a054d6ac1004f631c0ff0f5cd28f43b70f033..83b4d9f2c9c44f5599b6229fa9fbc97f2570ac77 100644 (file)
--- a/test/CodeGen/X86/mul-constant-i32.ll
+++ b/test/CodeGen/X86/mul-constant-i32.ll
@@ -1304,25 +1304,25 @@ define i32 @test_mul_by_26(i32 %x) {
 ; X86-LABEL: test_mul_by_26:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    leal (%ecx,%ecx,8), %eax
-; X86-NEXT:    leal (%eax,%eax,2), %eax
-; X86-NEXT:    subl %ecx, %eax
+; X86-NEXT:    leal (%ecx,%ecx,4), %eax
+; X86-NEXT:    leal (%eax,%eax,4), %eax
+; X86-NEXT:    addl %ecx, %eax
 ; X86-NEXT:    retl
 ;
 ; X64-HSW-LABEL: test_mul_by_26:
 ; X64-HSW:       # %bb.0:
 ; X64-HSW-NEXT:    # kill: def $edi killed $edi def $rdi
-; X64-HSW-NEXT:    leal (%rdi,%rdi,8), %eax # sched: [1:0.50]
-; X64-HSW-NEXT:    leal (%rax,%rax,2), %eax # sched: [1:0.50]
-; X64-HSW-NEXT:    subl %edi, %eax # sched: [1:0.25]
+; X64-HSW-NEXT:    leal (%rdi,%rdi,4), %eax # sched: [1:0.50]
+; X64-HSW-NEXT:    leal (%rax,%rax,4), %eax # sched: [1:0.50]
+; X64-HSW-NEXT:    addl %edi, %eax # sched: [1:0.25]
 ; X64-HSW-NEXT:    retq # sched: [7:1.00]
 ;
 ; X64-JAG-LABEL: test_mul_by_26:
 ; X64-JAG:       # %bb.0:
 ; X64-JAG-NEXT:    # kill: def $edi killed $edi def $rdi
-; X64-JAG-NEXT:    leal (%rdi,%rdi,8), %eax # sched: [2:1.00]
-; X64-JAG-NEXT:    leal (%rax,%rax,2), %eax # sched: [2:1.00]
-; X64-JAG-NEXT:    subl %edi, %eax # sched: [1:0.50]
+; X64-JAG-NEXT:    leal (%rdi,%rdi,4), %eax # sched: [2:1.00]
+; X64-JAG-NEXT:    leal (%rax,%rax,4), %eax # sched: [2:1.00]
+; X64-JAG-NEXT:    addl %edi, %eax # sched: [1:0.50]
 ; X64-JAG-NEXT:    retq # sched: [4:1.00]
 ;
 ; X86-NOOPT-LABEL: test_mul_by_26:

diff --git a/test/CodeGen/X86/mul-constant-i64.ll b/test/CodeGen/X86/mul-constant-i64.ll
index e241f849f9ebef1665cc4c8a97787c34de658fb7..32fe9378230346510434c61039e107c903687026 100644 (file)
--- a/test/CodeGen/X86/mul-constant-i64.ll
+++ b/test/CodeGen/X86/mul-constant-i64.ll
@@ -1358,9 +1358,9 @@ define i64 @test_mul_by_26(i64 %x) {
 ; X86-LABEL: test_mul_by_26:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X86-NEXT:    leal (%eax,%eax,8), %ecx
-; X86-NEXT:    leal (%ecx,%ecx,2), %ecx
-; X86-NEXT:    subl %eax, %ecx
+; X86-NEXT:    leal (%eax,%eax,4), %ecx
+; X86-NEXT:    leal (%ecx,%ecx,4), %ecx
+; X86-NEXT:    addl %eax, %ecx
 ; X86-NEXT:    movl $26, %eax
 ; X86-NEXT:    mull {{[0-9]+}}(%esp)
 ; X86-NEXT:    addl %ecx, %edx
@@ -1368,16 +1368,16 @@ define i64 @test_mul_by_26(i64 %x) {
 ;
 ; X64-HSW-LABEL: test_mul_by_26:
 ; X64-HSW:       # %bb.0:
-; X64-HSW-NEXT:    leaq (%rdi,%rdi,8), %rax # sched: [1:0.50]
-; X64-HSW-NEXT:    leaq (%rax,%rax,2), %rax # sched: [1:0.50]
-; X64-HSW-NEXT:    subq %rdi, %rax # sched: [1:0.25]
+; X64-HSW-NEXT:    leaq (%rdi,%rdi,4), %rax # sched: [1:0.50]
+; X64-HSW-NEXT:    leaq (%rax,%rax,4), %rax # sched: [1:0.50]
+; X64-HSW-NEXT:    addq %rdi, %rax # sched: [1:0.25]
 ; X64-HSW-NEXT:    retq # sched: [7:1.00]
 ;
 ; X64-JAG-LABEL: test_mul_by_26:
 ; X64-JAG:       # %bb.0:
-; X64-JAG-NEXT:    leaq (%rdi,%rdi,8), %rax # sched: [2:1.00]
-; X64-JAG-NEXT:    leaq (%rax,%rax,2), %rax # sched: [2:1.00]
-; X64-JAG-NEXT:    subq %rdi, %rax # sched: [1:0.50]
+; X64-JAG-NEXT:    leaq (%rdi,%rdi,4), %rax # sched: [2:1.00]
+; X64-JAG-NEXT:    leaq (%rax,%rax,4), %rax # sched: [2:1.00]
+; X64-JAG-NEXT:    addq %rdi, %rax # sched: [1:0.50]
 ; X64-JAG-NEXT:    retq # sched: [4:1.00]
 ;
 ; X86-NOOPT-LABEL: test_mul_by_26:

diff --git a/test/CodeGen/X86/mul-constant-result.ll b/test/CodeGen/X86/mul-constant-result.ll
index 2dd973a543bf24d3bbadc2d71208130bc51e6aa1..adac93d3959909ad376fea7abbf6af93d7efa035 100644 (file)
--- a/test/CodeGen/X86/mul-constant-result.ll
+++ b/test/CodeGen/X86/mul-constant-result.ll
@@ -193,10 +193,14 @@ define i32 @mult(i32, i32) local_unnamed_addr #0 {
 ; X86-NEXT:    retl
 ; X86-NEXT:  .LBB0_32:
 ; X86-NEXT:    .cfi_def_cfa_offset 8
-; X86-NEXT:    leal (%eax,%eax,8), %ecx
-; X86-NEXT:    leal (%ecx,%ecx,2), %ecx
-; X86-NEXT:    jmp .LBB0_12
+; X86-NEXT:    leal (%eax,%eax,4), %ecx
+; X86-NEXT:    leal (%ecx,%ecx,4), %ecx
+; X86-NEXT:    addl %ecx, %eax
+; X86-NEXT:    popl %esi
+; X86-NEXT:    .cfi_def_cfa_offset 4
+; X86-NEXT:    retl
 ; X86-NEXT:  .LBB0_33:
+; X86-NEXT:    .cfi_def_cfa_offset 8
 ; X86-NEXT:    leal (%eax,%eax,8), %eax
 ; X86-NEXT:    leal (%eax,%eax,2), %eax
 ; X86-NEXT:    popl %esi
@@ -369,9 +373,9 @@ define i32 @mult(i32, i32) local_unnamed_addr #0 {
 ; X64-HSW-NEXT:    # kill: def $eax killed $eax killed $rax
 ; X64-HSW-NEXT:    retq
 ; X64-HSW-NEXT:  .LBB0_29:
-; X64-HSW-NEXT:    leal (%rax,%rax,8), %ecx
-; X64-HSW-NEXT:    leal (%rcx,%rcx,2), %ecx
-; X64-HSW-NEXT:    jmp .LBB0_8
+; X64-HSW-NEXT:    leal (%rax,%rax,4), %ecx
+; X64-HSW-NEXT:    leal (%rcx,%rcx,4), %ecx
+; X64-HSW-NEXT:    jmp .LBB0_20
 ; X64-HSW-NEXT:  .LBB0_30:
 ; X64-HSW-NEXT:    leal (%rax,%rax,8), %eax
 ; X64-HSW-NEXT:    leal (%rax,%rax,2), %eax