[RISCV] Add (shl (zext GPR:), uimm5:) pattern for -riscv-experimental-rv64-legal-i32.

Author: topperc

llvm/lib/Target/RISCV/RISCVInstrInfo.td

@@ -2050,6 +2050,11 @@ def : Pat<(i32 (and GPR:$rs, TrailingOnesMask:$mask)),
 
 let Predicates = [IsRV64, NotHasStdExtZba] in {
 def : Pat<(zext GPR:$src), (SRLI (SLLI GPR:$src, 32), 32)>;
+
+// If we're shifting a 32-bit zero extended value left by 0-31 bits, use 2
+// shifts instead of 3. This can occur when unsigned is used to index an array.
+def : Pat<(shl (zext GPR:$rs), uimm5:$shamt),
+          (SRLI (SLLI GPR:$rs, 32), (ImmSubFrom32 uimm5:$shamt))>;
 }
 
 //===----------------------------------------------------------------------===//

llvm/test/CodeGen/RISCV/rv64-legal-i32/rv64zba.ll

@@ -50,8 +50,7 @@ define i128 @slliuw_3(i32 signext %0, ptr %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    addi a0, a0, 1
 ; RV64I-NEXT:    slli a0, a0, 32
-; RV64I-NEXT:    srli a0, a0, 32
-; RV64I-NEXT:    slli a0, a0, 4
+; RV64I-NEXT:    srli a0, a0, 28
 ; RV64I-NEXT:    add a1, a1, a0
 ; RV64I-NEXT:    ld a0, 0(a1)
 ; RV64I-NEXT:    ld a1, 8(a1)
@@ -1514,8 +1513,7 @@ define signext i32 @srliw_1_sh2add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    srliw a1, a1, 1
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 2
+; RV64I-NEXT:    srli a1, a1, 30
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    lw a0, 0(a0)
 ; RV64I-NEXT:    ret
@@ -1539,8 +1537,7 @@ define i64 @srliw_1_sh3add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    srliw a1, a1, 1
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 3
+; RV64I-NEXT:    srli a1, a1, 29
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    ld a0, 0(a0)
 ; RV64I-NEXT:    ret
@@ -1564,8 +1561,7 @@ define i64 @srliw_2_sh3add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    srliw a1, a1, 2
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 3
+; RV64I-NEXT:    srli a1, a1, 29
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    ld a0, 0(a0)
 ; RV64I-NEXT:    ret
@@ -1589,8 +1585,7 @@ define signext i16 @srliw_2_sh1add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    srliw a1, a1, 2
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 1
+; RV64I-NEXT:    srli a1, a1, 31
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    lh a0, 0(a0)
 ; RV64I-NEXT:    ret
@@ -1615,8 +1610,7 @@ define signext i32 @srliw_3_sh2add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    srliw a1, a1, 3
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 2
+; RV64I-NEXT:    srli a1, a1, 30
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    lw a0, 0(a0)
 ; RV64I-NEXT:    ret
@@ -1640,8 +1634,7 @@ define i64 @srliw_4_sh3add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    srliw a1, a1, 4
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 3
+; RV64I-NEXT:    srli a1, a1, 29
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    ld a0, 0(a0)
 ; RV64I-NEXT:    ret
@@ -1770,8 +1763,7 @@ define signext i16 @shl_2_sh1add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    slli a1, a1, 2
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 1
+; RV64I-NEXT:    srli a1, a1, 31
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    lh a0, 0(a0)
 ; RV64I-NEXT:    ret
@@ -1795,8 +1787,7 @@ define signext i32 @shl_16_sh2add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    slli a1, a1, 16
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 2
+; RV64I-NEXT:    srli a1, a1, 30
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    lw a0, 0(a0)
 ; RV64I-NEXT:    ret
@@ -1820,8 +1811,7 @@ define i64 @shl_31_sh3add(ptr %0, i32 signext %1) {
 ; RV64I:       # %bb.0:
 ; RV64I-NEXT:    slli a1, a1, 31
 ; RV64I-NEXT:    slli a1, a1, 32
-; RV64I-NEXT:    srli a1, a1, 32
-; RV64I-NEXT:    slli a1, a1, 3
+; RV64I-NEXT:    srli a1, a1, 29
 ; RV64I-NEXT:    add a0, a0, a1
 ; RV64I-NEXT:    ld a0, 0(a0)
 ; RV64I-NEXT:    ret