[RISCV][GISel] Fix failure to legalize non-power of 2 shifts between i32 and i64 on RV64.

We weren't legalizing the shift amount to i64.

Author: topperc

llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp

@@ -50,7 +50,8 @@ RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST) {
       .legalFor({{s32, s32}, {XLenLLT, XLenLLT}})
       .widenScalarToNextPow2(0)
       .clampScalar(1, s32, XLenLLT)
-      .clampScalar(0, s32, XLenLLT);
+      .clampScalar(0, s32, XLenLLT)
+      .minScalarSameAs(1, 0);
 
   if (ST.is64Bit()) {
     getActionDefinitionsBuilder({G_ZEXT, G_SEXT, G_ANYEXT})

llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv64/legalize-ashr.mir

@@ -359,3 +359,32 @@ body:             |
     PseudoRET implicit $x10, implicit $x11, implicit $x12
 
 ...
+---
+name:            ashr_i48
+body:             |
+  bb.0:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: ashr_i48
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $x11
+    ; CHECK-NEXT: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 16
+    ; CHECK-NEXT: [[SHL:%[0-9]+]]:_(s64) = G_SHL [[COPY]], [[C]](s64)
+    ; CHECK-NEXT: [[ASHR:%[0-9]+]]:_(s64) = G_ASHR [[SHL]], [[C]](s64)
+    ; CHECK-NEXT: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 281474976710655
+    ; CHECK-NEXT: [[AND:%[0-9]+]]:_(s64) = G_AND [[COPY1]], [[C1]]
+    ; CHECK-NEXT: [[ASHR1:%[0-9]+]]:_(s64) = G_ASHR [[ASHR]], [[AND]](s64)
+    ; CHECK-NEXT: $x10 = COPY [[ASHR1]](s64)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %2:_(s64) = COPY $x10
+    %0:_(s48) = G_TRUNC %2(s64)
+    %3:_(s64) = COPY $x11
+    %1:_(s48) = G_TRUNC %3(s64)
+    %4:_(s48) = G_ASHR %0, %1(s48)
+    %5:_(s64) = G_ANYEXT %4(s48)
+    $x10 = COPY %5(s64)
+    PseudoRET implicit $x10
+
+...

llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv64/legalize-lshr.mir

@@ -352,3 +352,31 @@ body:             |
     PseudoRET implicit $x10, implicit $x11, implicit $x12
 
 ...
+---
+name:            lshr_i48
+body:             |
+  bb.0:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: lshr_i48
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $x11
+    ; CHECK-NEXT: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 281474976710655
+    ; CHECK-NEXT: [[AND:%[0-9]+]]:_(s64) = G_AND [[COPY]], [[C]]
+    ; CHECK-NEXT: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 281474976710655
+    ; CHECK-NEXT: [[AND1:%[0-9]+]]:_(s64) = G_AND [[COPY1]], [[C1]]
+    ; CHECK-NEXT: [[LSHR:%[0-9]+]]:_(s64) = G_LSHR [[AND]], [[AND1]](s64)
+    ; CHECK-NEXT: $x10 = COPY [[LSHR]](s64)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %2:_(s64) = COPY $x10
+    %0:_(s48) = G_TRUNC %2(s64)
+    %3:_(s64) = COPY $x11
+    %1:_(s48) = G_TRUNC %3(s64)
+    %4:_(s48) = G_LSHR %0, %1(s48)
+    %5:_(s64) = G_ANYEXT %4(s48)
+    $x10 = COPY %5(s64)
+    PseudoRET implicit $x10
+
+...

llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv64/legalize-shl.mir

@@ -310,3 +310,29 @@ body:             |
     PseudoRET implicit $x10, implicit $x11, implicit $x12
 
 ...
+---
+name:            shl_i48
+body:             |
+  bb.0:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: shl_i48
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $x11
+    ; CHECK-NEXT: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 281474976710655
+    ; CHECK-NEXT: [[AND:%[0-9]+]]:_(s64) = G_AND [[COPY1]], [[C]]
+    ; CHECK-NEXT: [[SHL:%[0-9]+]]:_(s64) = G_SHL [[COPY]], [[AND]](s64)
+    ; CHECK-NEXT: $x10 = COPY [[SHL]](s64)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %2:_(s64) = COPY $x10
+    %0:_(s48) = G_TRUNC %2(s64)
+    %3:_(s64) = COPY $x11
+    %1:_(s48) = G_TRUNC %3(s64)
+    %4:_(s48) = G_SHL %0, %1(s48)
+    %5:_(s64) = G_ANYEXT %4(s48)
+    $x10 = COPY %5(s64)
+    PseudoRET implicit $x10
+
+...