[AArch64][GlobalISel] Recognise some CCMPri

This is a simple addition to emitConditionalComparison, to match CCMP
with immediates using getIConstantVRegValWithLookThrough, letting it
select the CCMPri variants of the instructions.

Differential Revision: https://reviews.llvm.org/D131073

2 files changed, 53 insertions, 93 deletions

diff --git a/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp b/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
index eb8d0552173d..1b1c2c4690d6 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
@@ -4821,8 +4821,13 @@ MachineInstr *AArch64InstructionSelector::emitConditionalComparison(
   LLT OpTy = MRI.getType(LHS);
   assert(OpTy.getSizeInBits() == 32 || OpTy.getSizeInBits() == 64);
   unsigned CCmpOpc;
+  Optional<ValueAndVReg> C;
   if (CmpInst::isIntPredicate(CC)) {
-    CCmpOpc = OpTy.getSizeInBits() == 32 ? AArch64::CCMPWr : AArch64::CCMPXr;
+    C = getIConstantVRegValWithLookThrough(RHS, MRI);
+    if (C && C->Value.ult(32))
+      CCmpOpc = OpTy.getSizeInBits() == 32 ? AArch64::CCMPWi : AArch64::CCMPXi;
+    else
+      CCmpOpc = OpTy.getSizeInBits() == 32 ? AArch64::CCMPWr : AArch64::CCMPXr;
   } else {
     switch (OpTy.getSizeInBits()) {
     case 16:
@@ -4841,7 +4846,12 @@ MachineInstr *AArch64InstructionSelector::emitConditionalComparison(
   AArch64CC::CondCode InvOutCC = AArch64CC::getInvertedCondCode(OutCC);
   unsigned NZCV = AArch64CC::getNZCVToSatisfyCondCode(InvOutCC);
   auto CCmp =
-      MIB.buildInstr(CCmpOpc, {}, {LHS, RHS}).addImm(NZCV).addImm(Predicate);
+      MIB.buildInstr(CCmpOpc, {}, {LHS});
+  if (C)
+    CCmp.addImm(C->Value.getZExtValue());
+  else
+    CCmp.addReg(RHS);
+  CCmp.addImm(NZCV).addImm(Predicate);
   constrainSelectedInstRegOperands(*CCmp, TII, TRI, RBI);
   return &*CCmp;
 }
diff --git a/llvm/test/CodeGen/AArch64/arm64-ccmp.ll b/llvm/test/CodeGen/AArch64/arm64-ccmp.ll
index 163cf55d4d74..eff39ed7a6da 100644
--- a/llvm/test/CodeGen/AArch64/arm64-ccmp.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-ccmp.ll
@@ -536,10 +536,9 @@ define i64 @gccbug(i64 %x0, i64 %x1) {
 ; GISEL-LABEL: gccbug:
 ; GISEL:       ; %bb.0:
 ; GISEL-NEXT:    mov w8, #2
-; GISEL-NEXT:    mov w9, #4
 ; GISEL-NEXT:    cmp x0, #2
-; GISEL-NEXT:    ccmp x0, x9, #4, ne
-; GISEL-NEXT:    ccmp x1, xzr, #0, eq
+; GISEL-NEXT:    ccmp x0, #4, #4, ne
+; GISEL-NEXT:    ccmp x1, #0, #0, eq
 ; GISEL-NEXT:    csinc x0, x8, xzr, eq
 ; GISEL-NEXT:    ret
   %cmp0 = icmp eq i64 %x1, 0
@@ -554,25 +553,14 @@ define i64 @gccbug(i64 %x0, i64 %x1) {
 }
 
 define i32 @select_ororand(i32 %w0, i32 %w1, i32 %w2, i32 %w3) {
-; SDISEL-LABEL: select_ororand:
-; SDISEL:       ; %bb.0:
-; SDISEL-NEXT:    cmp w3, #4
-; SDISEL-NEXT:    ccmp w2, #2, #0, gt
-; SDISEL-NEXT:    ccmp w1, #13, #2, ge
-; SDISEL-NEXT:    ccmp w0, #0, #4, ls
-; SDISEL-NEXT:    csel w0, w3, wzr, eq
-; SDISEL-NEXT:    ret
-;
-; GISEL-LABEL: select_ororand:
-; GISEL:       ; %bb.0:
-; GISEL-NEXT:    mov w8, #13
-; GISEL-NEXT:    mov w9, #2
-; GISEL-NEXT:    cmp w3, #4
-; GISEL-NEXT:    ccmp w2, w9, #0, gt
-; GISEL-NEXT:    ccmp w1, w8, #2, ge
-; GISEL-NEXT:    ccmp w0, wzr, #4, ls
-; GISEL-NEXT:    csel w0, w3, wzr, eq
-; GISEL-NEXT:    ret
+; CHECK-LABEL: select_ororand:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    cmp w3, #4
+; CHECK-NEXT:    ccmp w2, #2, #0, gt
+; CHECK-NEXT:    ccmp w1, #13, #2, ge
+; CHECK-NEXT:    ccmp w0, #0, #4, ls
+; CHECK-NEXT:    csel w0, w3, wzr, eq
+; CHECK-NEXT:    ret
   %c0 = icmp eq i32 %w0, 0
   %c1 = icmp ugt i32 %w1, 13
   %c2 = icmp slt i32 %w2, 2
@@ -585,21 +573,13 @@ define i32 @select_ororand(i32 %w0, i32 %w1, i32 %w2, i32 %w3) {
 }
 
 define i32 @select_andor(i32 %v1, i32 %v2, i32 %v3) {
-; SDISEL-LABEL: select_andor:
-; SDISEL:       ; %bb.0:
-; SDISEL-NEXT:    cmp w1, w2
-; SDISEL-NEXT:    ccmp w0, #0, #4, lt
-; SDISEL-NEXT:    ccmp w0, w1, #0, eq
-; SDISEL-NEXT:    csel w0, w0, w1, eq
-; SDISEL-NEXT:    ret
-;
-; GISEL-LABEL: select_andor:
-; GISEL:       ; %bb.0:
-; GISEL-NEXT:    cmp w1, w2
-; GISEL-NEXT:    ccmp w0, wzr, #4, lt
-; GISEL-NEXT:    ccmp w0, w1, #0, eq
-; GISEL-NEXT:    csel w0, w0, w1, eq
-; GISEL-NEXT:    ret
+; CHECK-LABEL: select_andor:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    cmp w1, w2
+; CHECK-NEXT:    ccmp w0, #0, #4, lt
+; CHECK-NEXT:    ccmp w0, w1, #0, eq
+; CHECK-NEXT:    csel w0, w0, w1, eq
+; CHECK-NEXT:    ret
   %c0 = icmp eq i32 %v1, %v2
   %c1 = icmp sge i32 %v2, %v3
   %c2 = icmp eq i32 %v1, 0
@@ -1001,24 +981,14 @@ define i32 @f128_select_and_olt_oge(fp128 %v0, fp128 %v1, fp128 %v2, fp128 %v3,
 ; This testcase resembles the core problem of http://llvm.org/PR39550
 ; (an OR operation is 2 levels deep but needs to be implemented first)
 define i32 @deep_or(i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %x, i32 %y) {
-; SDISEL-LABEL: deep_or:
-; SDISEL:       ; %bb.0:
-; SDISEL-NEXT:    cmp w2, #20
-; SDISEL-NEXT:    ccmp w2, #15, #4, ne
-; SDISEL-NEXT:    ccmp w1, #0, #4, eq
-; SDISEL-NEXT:    ccmp w0, #0, #4, ne
-; SDISEL-NEXT:    csel w0, w4, w5, ne
-; SDISEL-NEXT:    ret
-;
-; GISEL-LABEL: deep_or:
-; GISEL:       ; %bb.0:
-; GISEL-NEXT:    mov w8, #15
-; GISEL-NEXT:    cmp w2, #20
-; GISEL-NEXT:    ccmp w2, w8, #4, ne
-; GISEL-NEXT:    ccmp w1, wzr, #4, eq
-; GISEL-NEXT:    ccmp w0, wzr, #4, ne
-; GISEL-NEXT:    csel w0, w4, w5, ne
-; GISEL-NEXT:    ret
+; CHECK-LABEL: deep_or:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    cmp w2, #20
+; CHECK-NEXT:    ccmp w2, #15, #4, ne
+; CHECK-NEXT:    ccmp w1, #0, #4, eq
+; CHECK-NEXT:    ccmp w0, #0, #4, ne
+; CHECK-NEXT:    csel w0, w4, w5, ne
+; CHECK-NEXT:    ret
   %c0 = icmp ne i32 %a0, 0
   %c1 = icmp ne i32 %a1, 0
   %c2 = icmp eq i32 %a2, 15
@@ -1033,24 +1003,14 @@ define i32 @deep_or(i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %x, i32 %y) {
 
 ; Variation of deep_or, we still need to implement the OR first though.
 define i32 @deep_or1(i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %x, i32 %y) {
-; SDISEL-LABEL: deep_or1:
-; SDISEL:       ; %bb.0:
-; SDISEL-NEXT:    cmp w2, #20
-; SDISEL-NEXT:    ccmp w2, #15, #4, ne
-; SDISEL-NEXT:    ccmp w0, #0, #4, eq
-; SDISEL-NEXT:    ccmp w1, #0, #4, ne
-; SDISEL-NEXT:    csel w0, w4, w5, ne
-; SDISEL-NEXT:    ret
-;
-; GISEL-LABEL: deep_or1:
-; GISEL:       ; %bb.0:
-; GISEL-NEXT:    mov w8, #15
-; GISEL-NEXT:    cmp w2, #20
-; GISEL-NEXT:    ccmp w2, w8, #4, ne
-; GISEL-NEXT:    ccmp w0, wzr, #4, eq
-; GISEL-NEXT:    ccmp w1, wzr, #4, ne
-; GISEL-NEXT:    csel w0, w4, w5, ne
-; GISEL-NEXT:    ret
+; CHECK-LABEL: deep_or1:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    cmp w2, #20
+; CHECK-NEXT:    ccmp w2, #15, #4, ne
+; CHECK-NEXT:    ccmp w0, #0, #4, eq
+; CHECK-NEXT:    ccmp w1, #0, #4, ne
+; CHECK-NEXT:    csel w0, w4, w5, ne
+; CHECK-NEXT:    ret
   %c0 = icmp ne i32 %a0, 0
   %c1 = icmp ne i32 %a1, 0
   %c2 = icmp eq i32 %a2, 15
@@ -1065,24 +1025,14 @@ define i32 @deep_or1(i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %x, i32 %y) {
 
 ; Variation of deep_or, we still need to implement the OR first though.
 define i32 @deep_or2(i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %x, i32 %y) {
-; SDISEL-LABEL: deep_or2:
-; SDISEL:       ; %bb.0:
-; SDISEL-NEXT:    cmp w2, #20
-; SDISEL-NEXT:    ccmp w2, #15, #4, ne
-; SDISEL-NEXT:    ccmp w1, #0, #4, eq
-; SDISEL-NEXT:    ccmp w0, #0, #4, ne
-; SDISEL-NEXT:    csel w0, w4, w5, ne
-; SDISEL-NEXT:    ret
-;
-; GISEL-LABEL: deep_or2:
-; GISEL:       ; %bb.0:
-; GISEL-NEXT:    mov w8, #15
-; GISEL-NEXT:    cmp w2, #20
-; GISEL-NEXT:    ccmp w2, w8, #4, ne
-; GISEL-NEXT:    ccmp w1, wzr, #4, eq
-; GISEL-NEXT:    ccmp w0, wzr, #4, ne
-; GISEL-NEXT:    csel w0, w4, w5, ne
-; GISEL-NEXT:    ret
+; CHECK-LABEL: deep_or2:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    cmp w2, #20
+; CHECK-NEXT:    ccmp w2, #15, #4, ne
+; CHECK-NEXT:    ccmp w1, #0, #4, eq
+; CHECK-NEXT:    ccmp w0, #0, #4, ne
+; CHECK-NEXT:    csel w0, w4, w5, ne
+; CHECK-NEXT:    ret
   %c0 = icmp ne i32 %a0, 0
   %c1 = icmp ne i32 %a1, 0
   %c2 = icmp eq i32 %a2, 15