[PATCH] D146787: [X86] Teach computeKnownBitsForTargetNode about MUL_IMM

Kazu Hirata via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Mar 27 09:02:45 PDT 2023


This revision was automatically updated to reflect the committed changes.
Closed by commit rG258b5424edcf: [X86] Teach computeKnownBitsForTargetNode about MUL_IMM (authored by kazu).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D146787/new/

https://reviews.llvm.org/D146787

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/pr57402.ll
  llvm/test/CodeGen/X86/select-constant-lea.ll


Index: llvm/test/CodeGen/X86/select-constant-lea.ll
===================================================================
--- llvm/test/CodeGen/X86/select-constant-lea.ll
+++ llvm/test/CodeGen/X86/select-constant-lea.ll
@@ -8,8 +8,7 @@
 ; BASE-NEXT:    xorl %eax, %eax
 ; BASE-NEXT:    cmpl $10, %edi
 ; BASE-NEXT:    setae %al
-; BASE-NEXT:    leal (%rax,%rax,4), %eax
-; BASE-NEXT:    orl $8, %eax
+; BASE-NEXT:    leal 8(%rax,%rax,4), %eax
 ; BASE-NEXT:    retq
 ;
 ; SLOWLEA3-LABEL: select_unsigned_lt_10_8_13j:
@@ -18,7 +17,7 @@
 ; SLOWLEA3-NEXT:    cmpl $10, %edi
 ; SLOWLEA3-NEXT:    setae %al
 ; SLOWLEA3-NEXT:    leal (%rax,%rax,4), %eax
-; SLOWLEA3-NEXT:    orl $8, %eax
+; SLOWLEA3-NEXT:    addl $8, %eax
 ; SLOWLEA3-NEXT:    retq
   %2 = icmp ult i32 %0, 10
   %3 = select i1 %2, i32 8, i32 13
Index: llvm/test/CodeGen/X86/pr57402.ll
===================================================================
--- llvm/test/CodeGen/X86/pr57402.ll
+++ llvm/test/CodeGen/X86/pr57402.ll
@@ -6,8 +6,7 @@
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    notl %eax
 ; CHECK-NEXT:    andl $-2, %eax
-; CHECK-NEXT:    leal (%rax,%rax,2), %ecx
-; CHECK-NEXT:    orl $1, %ecx
+; CHECK-NEXT:    leal 1(%rax,%rax,2), %ecx
 ; CHECK-NEXT:    movswq %cx, %rsi
 ; CHECK-NEXT:    xorl %edi, %edi
 ; CHECK-NEXT:    movq $-1, %rax
Index: llvm/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -38282,6 +38282,13 @@
   Known.resetAll();
   switch (Opc) {
   default: break;
+  case X86ISD::MUL_IMM: {
+    KnownBits Known2;
+    Known = DAG.computeKnownBits(Op.getOperand(1), DemandedElts, Depth + 1);
+    Known2 = DAG.computeKnownBits(Op.getOperand(0), DemandedElts, Depth + 1);
+    Known = KnownBits::mul(Known, Known2);
+    break;
+  }
   case X86ISD::SETCC:
     Known.Zero.setBitsFrom(1);
     break;


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